HomeMy WebLinkAboutCUP 2023-0001; OMNI LA COSTA DRIVING RANGE EXPANSION; LIMITED GEOTECHNICAL INVESTIGATION; 2021-04-15LIMITED GEOTECHNICAL
INVESTIGATION
CHAMPIONS COURSE RENOVATIONS
OMNI LA COSTA RESORT & SPA
2100 COSTA DEL MAR ROAD
CARLSBAD, CALIFORNIA
PREPARED FOR
TRT HOLDINGS, INC.
DALLAS, TEXAS
APRIL 15, 2021
PROJECT NO. T2754-22-04
Project No. T2754-22-04
April 15, 2021
Mr. Clint Gulick
TRT Holdings, Inc.
4001 Maple Avenue, Suite 600
Dallas, Texas 75219
Subject: LIMITED GEOTECHNICAL INVESTIGATION
CHAMPIONS COURSE RENOVATIONS
ONMI LA COSTA RESORT & SPA
2100 COSTA DEL MAR ROAD
CARLSBAD, CALIFORNIA
Dear Mr. Gulick:
In accordance with your authorization of the work order authorization dated February 17, 2021,
Geocon West Inc. (Geocon) herein submits the results of our limited geotechnical investigation for the
subject site. The accompanying report presents the results of our study and conclusions and
recommendations pertaining to the geotechnical aspects of the proposed golf course renovations.
The site is considered suitable for 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.
Paul D. Theriault
CEG 2374
Joseph E. Vettel
GE 2401
PDT:JJV:hd
(e-mail) Addressee (Clint.Gulick@Omnihotels.com)
GEOCON
W E S T, I N C.
GEOTECHNICA L ■ ENVIRONMENTAL • MATE RI ALSO
41571 Corning Ploce, Suite l 01 ■ Murrieto, Colilornio 92562-7065 ■ Telephone 951.304.2300 ■ Fox 951 .304.2392
Geocon Project No. T2754-22-04 - i - April 15, 2021
TABLE OF CONTENTS
1. PURPOSE AND SCOPE ...................................................................................................................... 1
2. SITE AND PROJECT DESCRIPTION ................................................................................................ 1
3. GEOLOGIC SETTING ......................................................................................................................... 2
4. SOIL AND GEOLOGIC CONDITIONS ............................................................................................. 2
4.1 Undocumented Fill (afu) ............................................................................................................. 2
4.2 Young Alluvial Deposits (Qya) .................................................................................................. 2
5. GROUNDWATER ............................................................................................................................... 3
6. GEOLOGIC HAZARDS ...................................................................................................................... 3
6.1 Faulting ....................................................................................................................................... 3
6.2 Ground Rupture .......................................................................................................................... 5
6.3 Liquefaction ................................................................................................................................ 5
6.4 Expansive Soil ............................................................................................................................ 5
6.5 Seiches and Tsunamis ................................................................................................................. 5
6.6 Inundation ................................................................................................................................... 5
6.7 Landslides ................................................................................................................................... 6
6.8 Rock Fall Hazards....................................................................................................................... 6
6.9 Slope Stability ............................................................................................................................. 6
7. CONCLUSIONS AND RECOMMENDATIONS ................................................................................ 7
7.1 General ........................................................................................................................................ 7
7.2 Excavation and Soil Characteristics ........................................................................................... 8
7.3 Seismic Design Criteria ............................................................................................................ 10
7.4 Temporary Excavations ............................................................................................................ 12
7.5 Grading ..................................................................................................................................... 12
7.6 Earthwork Grading Factors ....................................................................................................... 14
7.7 Foundation and Concrete Slab-On-Grade Recommendations .................................................. 14
7.8 Concrete Flatwork .................................................................................................................... 15
7.9 Conventional Retaining Walls .................................................................................................. 16
7.10 Lateral Loading ......................................................................................................................... 18
7.11 Preliminary Pavement Recommendations ................................................................................ 18
7.12 Site Drainage and Moisture Protection ..................................................................................... 20
7.13 Grading and Foundation Plan Review ...................................................................................... 21
LIMITATIONS AND UNIFORMITY OF CONDITIONS
LIST OF REFERENCES
TABLE OF CONTENTS (Concluded)
Geocon Project No. T2754-22-04 - ii - April 15, 2021
MAPS AND ILLUSTRATIONS
Figure 1, Vicinity Map
Figure 2, Boring Location Map
Figure 3, Wall/Column Footing Detail
Figure 4, Typical Retaining Wall Drain Detail
APPENDIX A
FIELD INVESTIGATION Figures A-1 through A-6, Logs of Borings (Geocon, this report)
Figures A-7 through A-14, Logs of Borings (Geocon, 2002)
APPENDIX B
LABORATORY TESTING
Figure B-1, Laboratory Test Results
Figure B-2, Direct Shear Test Results
Figures B-3 and B-4, Laboratory Test Results (Geocon, 2002)
APPENDIX C RECOMMENDED GRADING SPECIFICATIONS
Geocon Project No. T2754-22-04 - 1 - April 15, 2021
LIMITED GEOTECHNICAL INVESTIGATION
1. PURPOSE AND SCOPE
This report presents the results of our limited geotechnical investigation for the renovations planned at
the Champions Course at the Omni La Costa Resort & Spa, located at 2100 Costa Del Mar Road,
Carlsbad, California as depicted on the Vicinity Map, Figure 1. The purpose of the limited geotechnical
investigation is to evaluate the surface and subsurface soil conditions and general site geology, and to
identify geotechnical constraints that may affect the proposed renovations. In addition, we provided
recommendations for remedial grading, shallow foundations, concrete flatwork, rigid pavement, and
retaining walls. This investigation also included a review of readily available published and
unpublished geologic literature (see List of References).
The scope of this investigation included performing a site reconnaissance, field exploration,
engineering analyses, and preparing this report. We performed our field investigation on
March 15, 2021, by drilling two small-diameter borings to a maximum depth of approximately
20 feet below the existing ground surface and advancing four hand auger borings to depths of
approximately 5 feet below the existing ground surface. The Boring Location Map, Figure 2, presents
the approximate locations of the borings. Appendix A provides a detailed discussion of the field
investigation including logs of the borings including boring logs from our 2002 geotechnical
investigation (Reference 18). Details of the laboratory tests and a summary of the test results are
presented in Appendix B and on the boring logs in Appendix A as well as laboratory data from our 2002
geotechnical investigation.
Recommendations presented herein are based on analyses of data obtained from our site investigation
and our understanding of proposed site development. If project details vary significantly from those
described herein, Geocon should be contacted to evaluate the necessity for review and possible revision
of this report.
2. SITE AND PROJECT DESCRIPTION
The subject site is the Champions Golf Course, part of the Omni La Costa Resort and Spa’s 36 hole,
two-course system, located at 2100 Costa Del Mar Road, Carlsbad, California. The Champions Course
generally runs in a north-south direction and is east of El Camino Real, south of Poinsettia Lane and
north of La Costa Avenue. The Course consists of an 18-hole, variable elevation course, with existing
tee boxes, cart paths, water hazards, sand traps, fairways and greens over and approximately
7,172-yard distance (black tees).
Based on a review of the Conceptual Plans prepared by Hanse Golf Course Design, Inc., we
understand that the proposed renovations will consist of adding and removing hazards, reshaping
Geocon Project No. T2754-22-04 - 2 - April 15, 2021
fairways and greens, realigning carts paths, adding a retaining wall near the 18th green, and foot bridges
spanning a creek between the 1st and 15th holes.
The site descriptions and proposed development are based on a site reconnaissance, review of
published geologic literature, our field investigation, a review of the conceptual plan, and discussions
with you.
3. GEOLOGIC SETTING
The site is located on wave cut platforms west of the Santa Ana Mountains within the Peninsular
Ranges Geomorphic Province (Province). In the vicinity of the site, the Province is characterized by
sandstone deposits on regionally uplifted wave cut platforms which display elevated erosional
surfaces surrounded by alluvium-filled valleys. The Santa Ana Mountains Block is characterized by
heterogeneous granitic bedrock with a moderate amount of volcanic and metamorphic rocks, and
some terrestrial sedimentary rocks. The Peninsular Ranges are bound by the Transverse Ranges
(San Gabriel and San Bernardino Mountains) to the north and the Colorado Desert Geomorphic
Province to the east. The Peninsular Ranges Geomorphic Province extends westward into the Pacific
Ocean and southward to the tip of Baja California. Overall, the Province is characterized by
Cretaceous-age granitic rock and a lesser amount of Mesozoic-age metamorphic rock overlain by
terrestrial and marine sediments. Faulting within the Province is typically northwest trending and
includes the San Andreas, San Jacinto, Elsinore, Newport-Inglewood and Rose Canyon faults.
4. SOIL AND GEOLOGIC CONDITIONS
We observed undocumented fill and young alluvial deposits during our field investigation.
The description of the geologic units encountered are shown on the boring logs in Appendix A. The
surficial soil and geologic units are described herein in order of increasing age.
4.1 Undocumented Fill (afu)
Undocumented Fill was encountered in all of the borings to depths ranging from one-half to one foot
and consisted of fine sandy clay that was damp to moist, stiff, dark brown; and silty fine to medium
sand that was damp, medium dense, and brown. Varying amounts of mica were observed in the
undocumented fill.
4.2 Young Alluvial Deposits (Qya)
Young Alluvial Deposits were encountered beneath the undocumented fill in all the borings to the
maximum depth drilled and consisted of sandy clay that was moist to saturated, stiff, dark brown with
varying amounts and size of sand to clayey fine to coarse sand that was saturated, medium dense to
silty sand that was moist, medium dense, and brown.
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5. GROUNDWATER
Groundwater was encountered in borings B-1 and B-2 at depths of 7.2 and 8.0 feet below the ground
surface, respectively. It is not uncommon for seepage conditions to develop where none previously
existed. Groundwater and seepage are 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 planned improvements.
6. GEOLOGIC HAZARDS
6.1 Faulting
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, formerly known as CDMG) for the Alquist-Priolo Earthquake Fault Zone Program
(Bryant and Hart, 2007). 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 or a San Diego County Safety Study Hazard Zone for surface fault rupture hazards. No active
or potentially active faults with the potential for surface fault rupture are known to pass directly
beneath the site. Therefore, the potential for surface rupture due to faulting occurring beneath the site
during the design life of the proposed school is considered low. However, the site is located in the
seismically active southern California region, and could be subjected to moderate to strong ground
shaking in the event of an earthquake on one of the many active southern California faults.
According to the Fault Activity Map of California (2010), 7 known active faults are located within a
search radius of 62 miles from the property. The nearest known active fault is Newport-Inglewood
Fault Zone located approximately 5.7 miles west of the site, and is the dominant source of potential
ground motion. Earthquakes that might occur on these fault zones or other faults within the southern
California and northern Baja California area are potential generators of significant ground motion at the
site. Table 6.1.1 lists the estimated maximum earthquake magnitude for the most dominant faults in
relationship to the site location.
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TABLE 6.1.1
SIGNIFICANT ACTIVE FAULTS WITHIN 100 KM OF THE SITE
Fault Direction Distance from
Site (Miles) Magnitude
Newport-Inglewood WSW 5.7 7.1
Coronado Bank WSW 20.3 7.2
Elsinore NE 22.9 6.8
San Diego Trough WSW 31.3 7.2
San Jacinto NE 49.8 6.9
Casa Loma NE 47.6 6.9
Rose Canyon S 60.1 7.2
Historic earthquakes in southern California of magnitude 6.0 and greater, their magnitude, distance,
and direction from the site are listed in Table 6.1.2.
TABLE 6.1.2
HISTORIC EARTHQUAKE EVENTS WITH RESPECT TO THE SITE
Earthquake Date of
Earthquake Magnitude
Distance to
Epicenter
(Miles)
Direction
to
Epicenter (Oldest to Youngest)
San Jacinto April 21, 1918 6.8 48 NNE
Loma Linda Area July 22, 1923 6.3 63 N
Long Beach March 10, 1933 6.4 54 NW
Buck Ridge March 25, 1937 6.0 62 ENE
Imperial Valley May 18, 1940 6.9 88 NE
Desert Hot Springs December 4, 1948 6.0 77 NE
Arroyo Salada March 19, 1954 6.4 70 E
Borrego Mountain April 8, 1968 6.5 72 E
San Fernando February 9, 1971 6.6 115 NW
Joshua Tree April 22, 1992 6.1 85 NE
Landers June 28, 1992 7.3 93 NE
Big Bear June 28, 1992 6.4 81 NNE
Northridge January 17, 1994 6.7 111 NW
Hector Mine October 16, 1999 7.1 121 NE
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6.2 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’s 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.
6.3 Liquefaction
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. Liquefaction is typified by a loss of shear strength in the liquefied layers
due to rapid increases in pore water pressure generated by earthquake accelerations. The proposed
retaining wall and foot bridges will be built on alluvial soils and liquefaction may be a design
consideration.
6.4 Expansive Soil
Previous work at the site (Geocon, 2017) has indicated that a “medium” expansion potential with
expansion indices of 74 and 78 as defined by ASTM D4829.
6.5 Seiches and Tsunamis
A seiche is a run-up of water within a lake or embayment triggered by fault- or landslide-induced
ground displacement. Batiquitos Lagoon is located approximately 2,000 feet west of the site.
However, due to an elevation gain of approximately 20 feet towards the site and the shallow nature
of the eastern portion of the lagoon, seiches are not a design consideration for the site.
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 first order driving force for locally generated tsunamis offshore southern
California is expected to be tectonic deformation from large earthquakes (Legg, et al., 2003).
Although the site is located 2.8 miles from the coast, and 2,000 feet from the mouth of the Batiquitos
Lagoon, a Tsunami Inundation Map for Emergency Planning prepared by the California Emergency
Management Agency indicates the site is not within a tsunami inundation zone; therefore, risk
associated with tsunamis is not a design consideration.
6.6 Inundation
According to the State of California, Department of Water Resources, Inundation Map for San Marcos
Dam, dated November 26, 1973, the site is within an inundation zone due to dam failure of the San
Marcos dam, and the California Department of Water Resources, Division of Safety of Dams (DSOD),
the site is within an inundation zone for the Stanley A. Mahr Reservoir.
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6.7 Landslides
There are no steep slopes on or adjacent to the site. Therefore, landslides are not a design consideration
for the site.
6.8 Rock Fall Hazards
Rock falls are not a design consideration due to the lack of natural bedrock slopes above and adjacent
to the site.
6.9 Slope Stability
Based on the preliminary site plan and relatively flat site topography, it does not appear that significant
slopes will be constructed. Therefore, slope stability will not be a design consideration for the site.
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7. CONCLUSIONS AND RECOMMENDATIONS
7.1 General
7.1.1 Neither soil nor geologic conditions were encountered during the investigation that would
preclude construction of the proposed project provided the recommendations presented herein
are followed and implemented during design and construction
7.1.2 Potential geologic hazards at the site include seismic shaking, liquefaction and seismic
settlement, and expansive soils. Based on our investigation and available geologic
information, active, potentially active, or inactive faults are not present underlying or
trending toward the site.
7.1.3 Our field investigation indicates the site consists of undocumented fill underlain by young
alluvial deposits. Undocumented fill and the upper portion of the alluvial soils are not
considered suitable for the support of compacted fill and settlement-sensitive structures.
Remedial grading of the surficial soil will be required as discussed herein. The existing site
soils are suitable for re-use as engineered fill provided the recommendations in the Grading
section of this report are followed.
7.1.4 Moisture contents in the borings were generally high. Drying back of overly wet soils or
importing of dryer material should be expected during construction.
7.1.5 Due to the high moisture content, caving in unshored excavations should be expected at the
site. It is the responsibility of the contractor to ensure that excavations and trenches are
properly shored and maintained in accordance with OSHA rules and regulations to maintain
the stability of adjacent existing improvements.
7.1.6 The laboratory tests on soils near the site indicate that the site soils are expansive and have a
“medium” expansion potential. If highly expansive soils are encountered in areas where
deformation sensitive improvements are planned, they should be exported from the site or
selectively graded and placed in the deeper fill areas to allow for the placement of low to
medium expansion material at the finish pad grade.
7.1.7 – Water soluble sulfate concentrations indicate Exposure Class S1 and S2 and will therefore
require Type II or Type V cement.
7.1.8 Groundwater was encountered at 7.2 and 8.0 feet below the existing ground surface in
borings B-1 and B-2, respectively. Groundwater could impact site improvements.
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7.1.9 The planned structures can be supported on a shallow foundation system with a slab-on-
grade floor system.
7.1.10 Changes in the design, location or elevation of improvements, as outlined in this report, should
be reviewed by this office. Once final grading plans become available, they should be
reviewed by this office to evaluate the necessity for review and possible revision of this
report.
7.1.11 Recommended grading specifications are provided in Appendix C.
7.2 Excavation and Soil Characteristics
7.2.1 Excavation of the in-situ soils can be excavated with moderate effort using conventional
excavation equipment. Some caving should be anticipated in unshored excavations,
especially where saturated soils are present.
7.2.2 It is the responsibility of the contractor to ensure that excavations and trenches are properly
shored and maintained in accordance with applicable OSHA rules and regulations to
maintain safety and the stability of existing adjacent improvements.
7.2.3 Onsite excavations must be conducted in such a manner that potential surcharges from
existing structures, construction equipment, and vehicle loads are resisted. The surcharge
area may be defined by a 1:1 projection down and away from the bottom of an existing
foundation or vehicle load. Penetrations below this 1:1 projection will require special
excavation measures such as sloping or shoring. Excavation recommendations are
provided in the Temporary Excavations section of this report.
7.2.4 The soil encountered in the field investigation is considered to be “expansive” (expansion
index [EI] of greater than 20) as defined by 2019 California Building Code (CBC) Section
1803.5.3. Table 7.2.4 presents soil classifications based on the expansion index. Based on the
laboratory test results of nearby soils, we expect a majority of the soil encountered will
possess a “medium” expansion potential (EI between 0 and 20). If highly expansive soils are
encountered at the site, they should not be placed within 4 feet of the proposed foundations,
flatwork or paving improvements. Additional testing for expansion potential should be
performed during grading and once final grades are achieved.
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TABLE 7.2.4
EXPANSION CLASSIFICATION BASED ON EXPANSION INDEX
Expansion Index (EI) ASTM D 4829 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
7.2.5 We performed laboratory tests on samples of the site materials to evaluate the
percentage of water-soluble sulfate content. Appendix B presents results of the laboratory
water-soluble sulfate content tests. The test results indicate the on-site materials at the
location tested possess a sulfate content of 0.100 to 1.390 percent (1,002 to 13,390 parts
per million [ppm]) equating to an exposure class of “S1” to “S2” as defined by 2019 CBC
Section 1904.3 and ACI 318. Table 7.2.5 presents a summary of concrete requirements set
forth by 2019 CBC Section 1904.3 and ACI 318. The presence of water-soluble sulfates is
not a visually discernible characteristic; therefore, other soil samples from the site could
yield different concentrations. Additionally, over time landscaping activities (i.e., addition
of fertilizers and other soil nutrients) may affect the concentration.
TABLE 7.2.5
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.
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7.2.6 Previous laboratory testing (Geocon, 2002) indicates the site soils have a minimum electrical
resistivity of 427 ohm-cm, and a pH of 8.0. As shown in Table 7.2.6 below, the site would be
classified as “corrosive” to buried improvements, in accordance with the Caltrans Corrosion
Guidelines (Caltrans, 2018).
TABLE 7.2.6
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
7.2.7 Geocon does not practice in the field of corrosion engineering. Therefore, further evaluation
by a corrosion engineer may be performed if improvements that could be susceptible to
corrosion are planned.
7.3 Seismic Design Criteria
7.3.1 The following table 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. The data
was calculated using the online application Seismic Design Maps, provided by OSHPD.
The short spectral response uses a period of 0.2 second. We evaluated the Site Class based
on the discussion in Section 1613.2.2 of the 2019 CBC and Table 20.3-1 of ASCE 7-16.
Although the site is subject to liquefaction resulting in Site Class F, because the period of
the planned structures is less than 0.5 seconds, values of Site Class D are applicable.
The values presented in Table 7.3.1 below are for the risk-targeted maximum considered
earthquake (MCER).
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TABLE 7.3.1
2019 CBC SEISMIC DESIGN PARAMETERS
Parameter Value 2016 CBC Reference
Site Class D Section 1613.3.2
MCER Ground Motion Spectral
Response Acceleration – Class B (short), SS 1.00g Figure 1613.3.1(1)
MCER Ground Motion Spectral
Response Acceleration – Class B (1 sec), S1 0.36g Figure 1613.3.1(2)
Site Coefficient, FA 1.3 Table 1613.3.3(1)
Site Coefficient, FV 1.94 Table 1613.3.3(2)
Site Class Modified MCER
Spectral Response Acceleration (short), SMS 1.20 Section 1613.3.3 (Eqn 16-37)
Site Class Modified MCER
Spectral Response Acceleration (1 sec), SM1 .704 Section 1613.3.3 (Eqn 16-38)
5% Damped Design
Spectral Response Acceleration (short), SDS 0.801 g Section 1613.3.4 (Eqn 16-39)
5% Damped Design
Spectral Response Acceleration (1 sec), SD1 0.469 Section 1613.3.4 (Eqn 16-40)
Note:
*Per Section 11.4.8 of ASCE/SEI 7-16, a ground motion hazard analysis shall 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. Using the code
based values presented in the table above, in lieu of performing a ground motion hazard analysis,
requires the exceptions outlined in ASCE 7-16 Section 11.4.8 be followed.
7.3.2 Table 7.3.2 presents additional seismic design parameters for projects located in Seismic
Design Categories of D through F in accordance with ASCE 7-16 for the mapped maximum
considered geometric mean (MCEG).
TABLE 7.3.2
2019 CBC SITE ACCELERATION PARAMETERS
Parameter Value ASCE 7-10 Reference
Site Class D Section 1613.3.2
Mapped MCEG
Peak Ground Acceleration, PGA 0.44g Figures 2 through 42-7
Site Coefficient, FPGA 1.2 Table 11.8-1
Site Class Modified MCEG
Peak Ground Acceleration, PGAM 0.527g Section 11.8.3 (Eqn 11.8-1)
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7.3.3 Conformance to the criteria in Tables 7.3.1 and 7.3.2 for seismic design does not constitute
any kind of guarantee or assurance that significant structural damage or ground 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.
7.4 Temporary Excavations
7.4.1 The recommendations included herein are provided for temporary excavations. It is the
responsibility of the contractor to provide a safe excavation during the construction of the
proposed project.
7.4.2 Excavations on the order of 5 to 10 feet in vertical height are expected during grading
operations and utility installation. The contractor’s competent person should evaluate the
necessity for lay back of vertical cut areas. Vertical excavations up to 5 feet may be
attempted where loose soils or caving sands are not present, and where not surcharged by
existing structures or vehicle/construction equipment loads.
7.4.3 Vertical excavations greater than 5 feet will require sloping measures in order to provide a
stable excavation. We expect that sufficient space is available to complete the majority of the
required earthwork for this project using sloping measures. If necessary, compound
excavation, slot-cutting, and or shoring recommendations will be provided in an addendum.
7.4.4 Where sloped embankments are utilized, the top of the slope should be barricaded to prevent
vehicles and storage loads at the top of the slope within a horizontal distance equal to the
height of the slope. If the temporary construction embankments are to be maintained during
the rainy season, berms are suggested along the tops of the slopes where necessary to prevent
runoff water from entering the excavation and eroding the slope faces. The contractor’s
personnel should inspect the soil exposed in the cut slopes during excavation so that
modifications of the slopes can be made if variations in the soil conditions occur.
Excavations should be stabilized within 30 days of initial excavation.
7.5 Grading
7.5.1 Grading should be performed in accordance with the recommendations provided in this
report, the Recommended Grading Specifications contained in Appendix C and City of
Carlsbad Standards.
7.5.2 Prior to commencing grading, a pre-construction conference should be held at the site with
the owner/developer, city inspector, grading contractor, civil engineer, and geotechnical
engineer in attendance. Special soil handling requirements can be discussed at that time.
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7.5.3 Site preparation should begin with the removal of previous structures and infrastructure,
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.
7.5.4 The undocumented fill and the upper portion of the alluvium in structural areas should be
removed to expose competent alluvium. Removals below structures should be extended
2 feet below the bottom of footings or pads and extend laterally two feet beyond the
footprint. Where the lateral over-excavation is not possible, deepened footings may be
required.
7.5.5 Removals in pavement and walkway areas should extend at least 2 feet beneath the pavement
or flatwork subgrade elevation.
7.5.6 The actual depth of removal should be evaluated by the engineering geologist during grading
operations. Deeper excavations may be required if loose, soft, or porous materials are present
at the base of the removals. The bottom of the excavations should be scarified to a depth of
at least 1 foot, moisture conditioned as necessary, and properly compacted.
7.5.7 The site should then be brought to final subgrade elevations with fill compacted in layers.
In general, soil native to the site is suitable for use as fill if free from vegetation, debris and
other deleterious material. If highly expansive soils (EI > 90) are encountered, they should
be placed more than 4 feet below planned improvements. Layers of fill should be about 6 to
8 inches in loose thickness and 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 in accordance with ASTM D 1557.
Fill materials placed below optimum moisture content may require additional moisture
conditioning prior to placing additional fill. The upper 12 inches of subgrade soil underlying
pavement should be 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 shortly before paving
operations.
7.5.8 Import fill soil (if necessary) should consist of granular materials with a “low” expansion
potential (EI of less than 50), free of deleterious material and rock fragments larger than
6 inches and should be compacted as recommended herein. Geocon should be notified of the
import soil source and should perform laboratory testing of import soil prior to its arrival at
the site to determine its suitability as fill material.
Geocon Project No. T2754-22-04 - 14 - April 15, 2021
7.5.9 Foundation excavation bottoms must be observed and approved in writing by the
Geotechnical Engineer, prior to placing fill, steel, gravel or concrete.
7.6 Earthwork Grading Factors
7.6.1 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 very approximate. 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 our
experience and the densities measured during our investigation, the shrinkage of
undocumented fill and alluvium soil is expected to be up to 10 percent when 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.
7.7 Foundation and Concrete Slab-On-Grade Recommendations
7.7.1 The foundation recommendations presented herein are for the proposed structures
subsequent to the recommended grading assuming that the structures are founded in soils
with a low to medium expansion potential. If soils with a high expansion potential are placed
within 4 feet of finish grade, then Geocon should be contacted for additional
recommendations. The proposed structure can be supported on a shallow foundation system
bearing in newly placed compacted fill.
7.7.2 Foundations for the structure should consist of either continuous strip footings and/or
isolated spread footings. Continuous footings should be at least 18 inches wide and extend at
least 18 inches below lowest adjacent pad grade. Isolated spread footings should have a
minimum width of 24 inches and should also extend at least 18 inches below lowest adjacent
pad grade. A wall/column footing dimension detail depicting footing embedment is provided
on Figure 3.
7.7.3 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.
Geocon Project No. T2754-22-04 - 15 - April 15, 2021
7.7.4 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.
7.7.5 The recommendations presented herein are based on soil characteristics only (EI of 90 or
less) and are not intended to replace steel reinforcement required for structural
considerations.
7.7.6 Foundations may be designed for an allowable soil bearing pressure of 3,000 pounds per
square foot (psf) (dead plus live load). The value presented herein is for dead plus live loads
and may be increased by one-third when considering transient loads due to wind or seismic
forces.
7.7.7 The maximum expected static settlement for the planned structures supported on
conventional foundation systems with the above allowable bearing pressure and deriving
support in engineered fill is estimated to be 1 inch and to occur below the heaviest loaded
structural element. Differential settlement is estimated to be on the order of ½ inch over a
horizontal distance of 40 feet. 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
7.7.8 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.
7.7.9 Special subgrade presaturation is not deemed necessary prior to placing concrete; however,
the exposed foundation subgrade soil should be moisturized to maintain a moist condition as
would be expected in any such concrete placement.
7.7.10 Geocon should be consulted to provide additional design parameters as required by the
structural engineer.
7.8 Concrete Flatwork
7.8.1 Exterior concrete flatwork not subject to vehicular traffic should be constructed in
accordance with the recommendations herein. Slab panels should be a minimum of 4 inches
thick and, when in excess of 8 feet square, should be reinforced with No. 3 reinforcing bars
spaced 24 inches on center in each direction to reduce the potential for wide cracking.
In addition, 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
Geocon Project No. T2754-22-04 - 16 - April 15, 2021
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 compacted 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 checked prior to placing concrete.
7.8.2 Even with the incorporation of the recommendations within this report, the exterior concrete
flatwork has a likelihood of experiencing some movement due to swelling or settlement;
therefore, 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.
7.8.3 Where exterior flatwork abuts structures 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.
7.8.4 The recommendations presented herein are intended to reduce the potential for cracking as a
result of differential movement. However, even with the incorporation of the
recommendations presented herein, concrete 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.
7.9 Conventional Retaining Walls
7.9.1 The recommendations presented herein are generally applicable to the design of rigid
concrete or masonry retaining walls having a maximum height of 10 feet. In the event that
walls higher than 10 feet or other types of walls are planned, Geocon should be consulted for
additional recommendations.
7.9.2 Retaining walls not restrained at the top and having a level backfill surface should be
designed for an active soil pressure equivalent to the pressure exerted by a fluid density of
35 pounds per cubic foot (pcf). Where the backfill will be inclined at no steeper than
2:1 (horizontal to vertical), an active soil pressure of 55 pcf is recommended. These soil
pressures assume that the backfill materials within an area bounded by the wall and a
Geocon Project No. T2754-22-04 - 17 - April 15, 2021
1:1 plane extending upward from the base of the wall possess an EI of 50 or less. For walls
where backfill materials do not conform to the criteria herein, Geocon should be consulted
for additional recommendations.
7.9.3 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 in feet) at the top of the wall. Where walls are
restrained from movement at the top, walls with a level backfill surface should be designed
for a soil pressure equivalent to the pressure exerted by a fluid density of 60 pcf.
7.9.4 The structural engineer should determine the seismic design category for the project in
accordance with Section 1613 of the CBC. If the project possesses a seismic design category
of D, E, or F, proposed retaining walls in excess of 6 feet in height should be designed with
seismic lateral pressure (Section 1803.5.12 of the 2019 CBC).
7.9.5 A seismic load of 10 pcf should be used for design of walls that support more than 6 feet of
backfill in accordance with Section 1803.5.12 of the 2019 CBC. The seismic load is applied
as an equivalent fluid pressure along the height of the wall and the calculated loads result in
a maximum load exerted at the base of the wall and zero at the top of the wall. This seismic
load should be applied in addition to the active earth pressure. The earth pressure is based on
half of two-thirds of PGAM calculated from ASCE 7-10 Section 11.8.3.
7.9.6 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.
7.9.7 Retaining walls should be provided with a drainage system adequate to prevent the buildup
of hydrostatic forces and waterproofed as required by the project architect. The soil
immediately adjacent to the backfilled retaining wall should be composed of free draining
material completely wrapped in Mirafi 140N (or equivalent) filter fabric for a lateral distance
of 1 foot for the bottom two-thirds of the height of the retaining wall. The upper one-third
should be backfilled with less permeable compacted fill to reduce water infiltration.
Alternatively, a drainage panel, such as a Miradrain 6000 or equivalent, can be placed along
the back of the wall. A typical drain detail for each option is shown on Figure 4. The use of
drainage openings through the base of the wall (weep holes) is not recommended where the
seepage could be a nuisance or otherwise adversely affect the property adjacent to the base
of the wall. The recommendations herein assume a properly compacted backfill (EI of 50 or
less) with no hydrostatic forces or imposed surcharge load. If conditions different than those
described are expected or if specific drainage details are desired, Geocon should be contacted
for additional recommendations.
Geocon Project No. T2754-22-04 - 18 - April 15, 2021
7.9.8 Wall foundations should be designed in accordance with the above foundation
recommendations.
7.10 Lateral Loading
7.10.1 To resist lateral loads, a passive pressure exerted by an equivalent fluid density of
300 pounds per cubic foot (pcf) should be used 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.
7.10.2 If friction is to be used to resist lateral loads, an allowable coefficient of friction between soil
and concrete of 0.35 should be used for design. The friction coefficient may be reduced
depending on the vapor barrier or waterproofing material used for construction in accordance
with the manufacturer’s recommendations.
7.10.3 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.
7.11 Preliminary Pavement Recommendations
7.11.1 In the event flexible pavements are constructed, we calculated flexible pavement sections in
general conformance with the Caltrans Method of Flexible Pavement Design (Highway
Design Manual, Section 608.4) and San Diego County specifications using a range of Traffic
Indices. The project civil engineer and owner should evaluate the final Traffic Index for the
pavements and review the pavement designations to determine appropriate locations for
pavement thickness. Based on the laboratory testing of the onsite soils, we have used a
preliminary R-value of 7 for the subgrade soils for the purposes of this analysis. The final
pavement sections should be based on the R-value of the subgrade soil encountered at final
subgrade elevation. Table 7.11.1 presents the preliminary flexible pavement sections.
TABLE 7.11.1
PRELIMINARY FLEXIBLE PAVEMENT SECTION
Location
Assumed
Traffic
Index
Subgrade
R-Value
Asphalt
Concrete
(inches)
Class 2
Aggregate
Base (inches)
Driveways for automobiles
and light-duty vehicles 5.5
7
3.0 11.5
Medium truck traffic areas 6.0 3.5 12.5
Driveways for heavy truck and fire truck traffic 7.0 4.0 15.0
Geocon Project No. T2754-22-04 - 19 - April 15, 2021
7.11.2 Prior to placing base materials, the upper 12 inches of the subgrade soil should be scarified,
moisture conditioned as necessary, and recompacted to a dry density of at least 95 percent of
the laboratory maximum dry density at 0 to 2 percent above optimum moisture content as
determined by ASTM D 1557. Similarly, the base material should be 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. Asphalt concrete should be compacted to a density of at least
95 percent of the laboratory Hveem density in accordance with ASTM D 2726.
7.11.3 Base materials should conform to Section 26-1.028 of the Standard Specifications for
The State of California Department of Transportation (Caltrans). The asphalt concrete
should conform to Section 203-6 of the Standard Specifications for Public Works
Construction (Greenbook).
7.11.4 A rigid Portland cement concrete (PCC) pavement section should be placed in heavy truck
areas, 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 Guide for Design and Construction of Concrete Parking Lots using the
parameters presented in Table 7.11.4.
TABLE 7.11.4
RIGID PAVEMENT DESIGN PARAMETERS
Design Parameter Design Value
Modulus of subgrade reaction, k 200 pci
Modulus of rupture for concrete, MR 500 psi
Traffic Category, TC C and D
Average daily truck traffic, ADTT 100 and 700
7.11.5 Based on the criteria presented herein, the PCC pavement sections should have a minimum
thickness as presented in Table 7.11.5.
TABLE 7.11.5
RIGID PAVEMENT RECOMMENDATIONS
Location Portland Cement Concrete (inches)
Cart Paths (no heavy truck traffic) 4.0
Automobile Parking Stalls (TC=C) 6.5
Heavy Truck and Fire Lane Areas (TC=D) 7.5
Geocon Project No. T2754-22-04 - 20 - April 15, 2021
7.11.6 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 3,500 psi (pounds per square inch).
7.11.7 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., 6-inch and
7.5-inch-thick slabs would have an 8- and 9.5-inch-thick edge, respectively). Reinforcing
steel will not be necessary within the concrete for geotechnical purposes with the possible
exception of dowels at construction joints as discussed herein.
7.11.8 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.
7.11.9 The performance of 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.
7.12 Site Drainage and Moisture Protection
7.12.1 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.
Geocon Project No. T2754-22-04 - 21 - April 15, 2021
7.12.2 In the case of walls retaining landscaping areas, a water-proofing system should be used on
the wall and joints, and a Miradrain drainage panel (or similar) should be placed over the
waterproofing. The project architect or civil engineer should provide detailed specifications
on the plans for all waterproofing and drainage.
7.12.3 Landscape planters that saturate the subsurface should not be used within 20 feet of the
proposed structure or other settlement sensitive on grade improvements. Localized surface
settlement should be anticipated in areas where water is allowed to infiltrate into the
subsurface.
7.12.4 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.
7.12.5 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. Area drains
to collect excess irrigation water and transmit it to drainage structures or impervious
above-grade planter boxes can be used. In addition, where landscaping is planned adjacent to
the pavement, construction of a cutoff wall along the edge of the pavement that extends at
least 6 inches below the bottom of the base material should be considered.
7.12.6 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 water
infiltration.
7.13 Grading and Foundation Plan Review
7.13.1 Geocon should review the project grading and foundation plans prior to final design
submittal to verify that the plans have been prepared in substantial conformance with the
recommendations of this report and to provide additional analyses or recommendations, if
necessary.
Geocon Project No. T2754-22-04 April 15, 2021
LIMITATIONS AND UNIFORMITY OF CONDITIONS
1. 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 presented 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.
2. 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 or corrosive materials was not part of the scope of
services provided by Geocon.
3. This report is issued with the understanding that it is the responsibility of the owner or 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.
4. The findings of this report are valid as of the date of this report. However, changes in the
conditions of a property can occur with the passage of time, whether they be 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.
Geocon Project No. T2754-22-04 - 1 - April 15, 2021
LIST OF REFERENCES
1. 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.
2. American Concrete Institute, 2008, 330R Guide for the Design and Construction of Concrete
Parking Lots, American Concrete Institute Committee 330, dated June.
3. American Concrete Institute, 2006, 302.2R Guide for Guide for Concrete Slabs that Receive
Moisture-Sensitive Flooring Materials, American Concrete Institute Committee 302.
4. Anderson, J. G., T. K. Rockwell, and D. C. Agnew, 1989, Past and Possible Future
Earthquakes of Significance to the San Diego Region: Earthquake Spectra, v.5, no. 2,
p.299-333.
5. ASCE 7-16, 2018, 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, pp. 99-138, 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 Guidelines, Version 3.0,
dated March.
10. Caltrans, 2017, Highway Design Manual, Sixth Edition.
11. Caltrans, 2015, Standard Specifications.
12. California Geological Survey, 2002, Seismic Shaking Hazards in California, Based on the
USGS/CGS Probabilistic Seismic Hazards Assessment (PSHA) Model, (revised April 2003).
10% probability of being exceeded in 50 years.
http://redirect.conservation.ca.gov/cgs/rghm/pshamap/pshamain.html
13. California Geologic Survey, 2008, Special Publication 117A, Guidelines for Evaluating and
Mitigating Seismic Hazards in California, Revised and Re-adopted September 11.
14. 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.
LIST OF REFERENCES (Continued)
Geocon Project No. T2754-22-04 April 15, 2021
15. Carlsbad General Plan, available at www.carlsbadca.gov/services/depts/planning/update/
documents.asp, accessed January 30, 2016.
16. Carlsbad, Engineering Standards, Volume 3, Standard Drawings and Specifications,
dated 2004.
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.
18. Geocon Inc, 2002, Geotechnical Investigation, La Costa Trunk Sewer, La Costa California,
Project No. 06796-22-01, revised July 17
19. Google Inc., Google Maps online mapping software, accessed January 24, 2017.
20. Google Inc., Google Earth Pro, Version 7.1.2.2041, accessed January 24, 2017.
21. Harden, D.R., California Geology, Prentice-Hall, Inc., 479 pp., 1998.
22. Jennings, C. W., 2010, California Division of Mines and Geology, Fault Activity Map of
California and Adjacent Areas, California Geologic Data Map Series Map No. 6.
23. Legg, M. R., J. C. Borrero, and C. E. Synolakis, Evaluation of Tsunami Risk to Southern
California Coastal Cities, 2002 NEHRP Professional Fellowship Report, dated January 2003.
24. Morton, D.M., Preliminary Digital Geologic Map of the Santa Ana 30’x60’ Quadrangle,
Southern California.
25. OSPD, 2018, Seismic Design Maps, https://seismicmaps.org Accessed November 18, 2018.
26. Public Works Standards, Inc., 2018, Standard Specifications for Public Works Construction
“Greenbook,” Published by BNi Building News.
27. Tan, S.S., and Kennedy, M. P. 1996, Geologic Map of the Encinitas and Rancho Santa Fe
7.5’ Quadrangles, San Diego County, California, in DMG OFR 96-02.
28. Unpublished Geotechnical Reports and Information, Geocon West, Inc.
SOURCE: Google Earth, 2021
VICINITY MAP
CHAMPIONS COURSE RENOVATIONS
OMNI LA COSTA RESORT & SPA
2100 COSTA DEL MAR ROAD
CARLSBAD, CALIFORNIA
APRIL 2021 PROJECT NO. T2754-22-04 FIG. 1LCW
PROJECT
BOUNDARY
SCALE: 1” = 3000’
0’ 3000’ 6000’
La Costa Avenue
GEOCON
W E S T , I N C.
GEOTECHNICAL, ENVIRONMENTAL, MATERIALS
41571 CORNING PLACE #101 , MURRIETA, CALIFORNIA 92562
PHONE 951 -304-2300 FAX 951-304-2392
I I
BORING LOCATION MAP
APRIL 2021 PROJECT NO. T754-22-04 FIG. 2LCW
CHAMPIONS COURSE RENOVATIONS
OMNI LA COSTA RESORT & SPA
2100 COSTA DEL MAR ROADCARLSBAD, CALIFORNIA
SOURCE: Google Earth 2021 SCALE 1” = 800’
0 800 1600
GEOCON LEGEND
Locations are approximate
B-6 ……. BORING LOCATION
(GEOCON, THIS REPORT)
B-8 ……. BORING LOCATION
(GEOCON, 2002)
.….. PROJECT LIMITS
B-3
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GEOCON
W E S T , I N C.
GEOTECHNICAL ENVIRONMENTAL MATERIALS
41571 CORNING PLACE, SUITE 101 , MURRIETA, CA 92562
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%'-..':/);:/A ~ ~ \
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I
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..
....
.....
...................
.
............
..
...
APRIL 2021 PROJECT NO. T2745-22-04 FIG. 4PDT
TYPICAL RETAINING WALL DRAIN DETAIL
NOTES:
DRAIN SHOULD BE UNFORMLY SLOPED TO GRAVITY OUTLET
OR TO A SUMP WHERE WATER CAN BE REMOVED BY PUMPIMG
CONCRETE BROW DITCH RECOMMENDED FOR SLOPE HEIGHTS
GREATER THAN 6 FEET
2/3 H
GROUND SURFACE
CONCRETE
BROWDITCH
PROPOSED
RETAINING WALL
GROUND SURFACE
FOOTING
TEMPORARY BACKCUT
PER OSHA
MIRAFI 140N FILTER FABRIC
(OR EQUIVALENT)
OPEN‐GRADED
¾” MAX. AGGREGATE
4” DIA. PERFORATED SCHEDULE
40 PVC PIPE EXTENDED TO
APPROVED OUTLET
1”
12”
.
2/3 H
GROUND SURFACE
CONCRETE
BROWDITCH
PROPOSED
RETAINING WALL
PROPOSED
GRADE
FOOTING
MIRAFI 140N FILTER FABRIC
(OR EQUIVALENT)
OPEN‐GRADED
¾” MAX. AGGREGATE
(1 CU. FT./FT.)
4” DIA. PERFORATED SCHEDULE
40 PVC PIPE EXTENDED TO
APPROVED OUTLET
12”
....
....
..
WATER PROOFING
PER ARCHITECT
PROPERLY
COMPACTED
BACKFILL
WATER PROOFING
PER ARCHITECT
DRAINAGE PANEL (MIRADRAIN 6000
OR EQUIVALENT)
NO SCALE
CHAMPIONS COURSE RENOVATIONS
OMNI LA COSTA RESORT & SPA
2100 COSTA DEL MAR ROAD
CARLSBAD, CALIFORNIA
GEOCON
W E S T , I N C.
GEOTECHNICAL ENVIRONMENTAL MATERIALS
41571 CORNING PLACE, SUITE 101, MURRIETA, CA 92562-7065
PHONE 951-304-2300 FAX 951-304-2392
I I
APPENDIX A
Geocon Project No. T2754-22-04 -A- April 15, 2021
APPENDIX A
FIELD INVESTIGATION
Field work for our investigation included a site reconnaissance, subsurface exploration, and soil
sampling. The Boring Location Map, Figure 2 presents the locations of the exploratory borings.
Boring logs and an explanation of the geologic units encountered are presented in figures following
the text in this appendix. We located the borings in the field using existing reference points.
Therefore, actual boring locations may deviate slightly. We performed a field investigation on
March 15, 2021 which consisted of drilling 2 exploratory borings to a maximum depth of
approximately 19.5 feet below existing grade with a CME 75 drill rig equipped with 8-inch-diameter
hollow-stem auger and 4 hand auger borings to depths of 5 feet below existing grade.
We collected bulk and relatively undisturbed samples from the borings by driving a 3-inch O. D.,
California Modified Sampler into the “undisturbed” soil mass with blows from a 140-pound hammer
falling 30 inches on an auto hammer. The California Modified Sampler was equipped with 1-inch
high by 23/8-inch inside diameter brass sampler rings to facilitate removal and testing. Relatively
undisturbed samples and bulk samples of disturbed soils were transported to our laboratory for
testing. The type of sample is noted on the exploratory boring logs.
The samplers were driven 18 inches into the bottom of the excavations. Blow counts are recorded for
every 6 inches the sampler is driven. The penetration resistances shown on the boring logs are shown
in terms of blows per foot. The values indicated on the boring logs are the sum of the last 12 inches of
the sampler if driven 18 inches. If the sampler was not driven for 18 inches, an approximate value is
calculated in term of blows per foot or the final 6-inch interval is reported. These values are not to be
taken as N-values; adjustments have not been applied. We estimated elevations shown on the boring
logs from Google Earth.
We visually examined the soil conditions encountered within the borings, classified, and logged in
general accordance with the Unified Soil Classification System (USCS). Logs of the borings are
presented on Figures A-1 through A-6. Logs of borings from a previous investigation (Geocon, 2002)
are presented on Figures A-7 through A-14. The logs depict the general soil and geologic conditions
encountered and the depth at which we obtained the samples.
96.0
101.7
99.0
99.7
99.7
27
21
15
19
19
14
CL
CL
SC
B-1@0-5'
B-1@2.5'
B-1@5.0'
B-1@7.5'
B-1@10.0''
B-1@15.0'
B-1@18.0'
UNDOCUMENTED FILL (afu)
sandy CLAY, stiff, moist, dark brown; fine sand; micaceous; grass on
surface
YOUNG ALLUVIAL DEPOSITS (Qya)
Sandy CLAY, moist, stiff, dark brown; fine sand; micaceous
-Becomes wet
-Becomes saturated
-Becomes fine to coarse sand, light brown with some gray
Clayey SAND, medium dense, saturated, light brown with reddish yellow
staining; fine to coarse sand
Total depth 19.5 feet
Groundwater stabilized at 7.2 feet
Penetration resistance for 140 lb. hammer falling 30" by auto hammer
Backfilled with curttings on 3/15/2021
20.8
25.1
24.3
21.1
25.8
PE
N
E
T
R
A
T
I
O
N
... DRIVE SAMPLE (UNDISTURBED)
HOLLOW STEM AUGERLI
T
H
O
L
O
G
Y
GR
O
U
N
D
W
A
T
E
R
SOIL
CLASS
(USCS)
SAMPLE SYMBOLS
DATE COMPLETED
(P
.
C
.
F
.
)
GEOCON
Figure A-1,
Log of Boring B-1, Page 1 of 1
... DISTURBED OR BAG SAMPLE
0
2
4
6
8
10
12
14
16
18
SAMPLE
NO.
RE
S
I
S
T
A
N
C
E
21
EQUIPMENT
ELEV. (MSL.)
... CHUNK SAMPLE
BORING B-1
DR
Y
D
E
N
S
I
T
Y
DEPTH
IN
FEET
... WATER TABLE OR SEEPAGE
3/15/21
P. THERIAULTBY:
T2754-22-04 BORING LOGS.GPJ
(B
L
O
W
S
/
F
T
.
)
... SAMPLING UNSUCCESSFUL
CO
N
T
E
N
T
(
%
)
... STANDARD PENETRATION TEST
MATERIAL DESCRIPTION
MO
I
S
T
U
R
E
BU
L
K
DR
/
S
P
T
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.
T2754-22-04
,--// ~ -~ 1// ~ ,--~ ½ ~ -~
,--~
~ ½ ~ -
,--½ ~ -"¥-
,--½ ~ -
,--½ ~ -½ ,--
~ -½ ,--
~ -½ ,--~ ~ -
?/-/ ,---·/ (//
~ -<-//
----
I
----------------------------------
I]
liiiiJ
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-----------
-
98.4
90.6
87.9
86.5
87.8
20
17
7
14
9
13
CL
CL
SC
CL
B-2@0-5.0'
B-2@2.5'
B-2@5.0'
B-2@7.5'
B-2@10.0'
B-2@15.0'
B-2@18.0'
UNDOCUMENTED FILL (afu)
sandy CLAY, stiff, moist, dark brown; fine sand; micaceous; grass on
surface
YOUNG ALLUVIAL DEPOSITS (Qya)
Sandy CLAY, moist, stiff, dark brown; fine sand; micaceous
Clayey SAND, medium dense, moist, reddish brown; fine to coarse sand;
micaceous
Sandy CLAY, stiff, wet, dark brown; fine sand; some medium sand;
micaceous
-Becomes saturated, black
-Becomes gray with red staining; fine sand
Total depth 19.5 feet
Groundwater stabilized at 8.0 feet
Penetration resistance for 140 lb. hammer falling 30" by auto hammer
Backfilled with curttings on 3/15/2021
21.1
35.2
36.1
28.2
37.2
PE
N
E
T
R
A
T
I
O
N
... DRIVE SAMPLE (UNDISTURBED)
HOLLOW STEM AUGERLI
T
H
O
L
O
G
Y
GR
O
U
N
D
W
A
T
E
R
SOIL
CLASS
(USCS)
SAMPLE SYMBOLS
DATE COMPLETED
(P
.
C
.
F
.
)
GEOCON
Figure A-2,
Log of Boring B-2, Page 1 of 1
... DISTURBED OR BAG SAMPLE
0
2
4
6
8
10
12
14
16
18
SAMPLE
NO.
RE
S
I
S
T
A
N
C
E
12
EQUIPMENT
ELEV. (MSL.)
... CHUNK SAMPLE
BORING B-2
DR
Y
D
E
N
S
I
T
Y
DEPTH
IN
FEET
... WATER TABLE OR SEEPAGE
3/15/21
P. THERIAULTBY:
T2754-22-04 BORING LOGS.GPJ
(B
L
O
W
S
/
F
T
.
)
... SAMPLING UNSUCCESSFUL
CO
N
T
E
N
T
(
%
)
... STANDARD PENETRATION TEST
MATERIAL DESCRIPTION
MO
I
S
T
U
R
E
BU
L
K
DR
/
S
P
T
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.
T2754-22-04
,--// ~ -~ (-Ii) ~ ,--------~ ;-_/;; ~ -~ ;// ,--~
~ ✓/f
~ -"'/ ,
1// ,--
~ -½ ,--"¥-½ ~ -
,--½ ~ -
,--½ ~ -
,--½ ~ -½ ,--
~ -~ ,--
~ -
I
h ,----
\ I L _______________________________ J -
I]
liiiiJ
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
r--------
SM
SM
B-3@0-5.0'UNDOCUMENTED FILL (afu)
Silty SAND, damp, light brown, moist; fine to medium sand; some
coarse sand; micaceous
YOUNG ALLUVIAL DEPOSITS (Qya)
Silty SAND, moist, medium dense, brown; fine to medium sand;
micaceous
Total depth 5.0 feet
Groundwater not encountered
Backfilled with cuttings on 3/15/2021
PE
N
E
T
R
A
T
I
O
N
... DRIVE SAMPLE (UNDISTURBED)
HAND AUGERLI
T
H
O
L
O
G
Y
GR
O
U
N
D
W
A
T
E
R
SOIL
CLASS
(USCS)
SAMPLE SYMBOLS
DATE COMPLETED
(P
.
C
.
F
.
)
GEOCON
Figure A-3,
Log of Hand Auger B-3, Page 1 of 1
... DISTURBED OR BAG SAMPLE
0
2
4
SAMPLE
NO.
RE
S
I
S
T
A
N
C
E
122
EQUIPMENT
ELEV. (MSL.)
... CHUNK SAMPLE
HAND AUGER B-3
DR
Y
D
E
N
S
I
T
Y
DEPTH
IN
FEET
... WATER TABLE OR SEEPAGE
3/15/21
P. THERIAULTBY:
T2754-22-04 BORING LOGS.GPJ
(B
L
O
W
S
/
F
T
.
)
... SAMPLING UNSUCCESSFUL
CO
N
T
E
N
T
(
%
)
... STANDARD PENETRATION TEST
MATERIAL DESCRIPTION
MO
I
S
T
U
R
E
BU
L
K
DR
/
S
P
T
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.
T2754-22-04
,--
~ -~
~ ,--~
~ -~
~ ,--
~
~
.1 1_-1_
:-1. 7-l
l~ ·1
:-l rl-
.-1-l
:i--! ·1
I]
liiiiJ
-
-
-
-
SM
SM
B-4@0-5.0'UNDOCUMENTED FILL (afu)
Silty SAND, damp, light brown, moist; fine to medium sand; some
coarse sand; micaceous
YOUNG ALLUVIAL DEPOSITS (Qya)
Silty SAND, moist, medium dense, brown; fine to medium sand;
micaceous
Total depth 5.0 feet
Groundwater not encountered
Backfilled with cuttings on 3/15/2021
PE
N
E
T
R
A
T
I
O
N
... DRIVE SAMPLE (UNDISTURBED)
HAND AUGERLI
T
H
O
L
O
G
Y
GR
O
U
N
D
W
A
T
E
R
SOIL
CLASS
(USCS)
SAMPLE SYMBOLS
DATE COMPLETED
(P
.
C
.
F
.
)
GEOCON
Figure A-4,
Log of Hand Auger B-4, Page 1 of 1
... DISTURBED OR BAG SAMPLE
0
2
4
SAMPLE
NO.
RE
S
I
S
T
A
N
C
E
135
EQUIPMENT
ELEV. (MSL.)
... CHUNK SAMPLE
HAND AUGER B-4
DR
Y
D
E
N
S
I
T
Y
DEPTH
IN
FEET
... WATER TABLE OR SEEPAGE
3/15/21
P. THERIAULTBY:
T2754-22-04 BORING LOGS.GPJ
(B
L
O
W
S
/
F
T
.
)
... SAMPLING UNSUCCESSFUL
CO
N
T
E
N
T
(
%
)
... STANDARD PENETRATION TEST
MATERIAL DESCRIPTION
MO
I
S
T
U
R
E
BU
L
K
DR
/
S
P
T
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.
T2754-22-04
,--
~ -~
~ ,--~
~ -~
~ ,--
~
~
.1 1_-1_
:-1. 7-l
l~ ·1
:-l rl-
.-1-l
:i--! ·1
I]
liiiiJ
-
-
-
-
SM
SM
B-5@0-5.0'UNDOCUMENTED FILL (afu)
Silty SAND, damp, light brown, moist; fine to medium sand; some
coarse sand; micaceous
YOUNG ALLUVIAL DEPOSITS (Qya)
Silty SAND, moist, medium dense, brown; fine to medium sand;
micaceous
Total depth 5.0 feet
Groundwater not encountered
Backfilled with cuttings on 3/15/2021
PE
N
E
T
R
A
T
I
O
N
... DRIVE SAMPLE (UNDISTURBED)
HAND AUGERLI
T
H
O
L
O
G
Y
GR
O
U
N
D
W
A
T
E
R
SOIL
CLASS
(USCS)
SAMPLE SYMBOLS
DATE COMPLETED
(P
.
C
.
F
.
)
GEOCON
Figure A-5,
Log of Hand Auger B-5, Page 1 of 1
... DISTURBED OR BAG SAMPLE
0
2
4
SAMPLE
NO.
RE
S
I
S
T
A
N
C
E
96
EQUIPMENT
ELEV. (MSL.)
... CHUNK SAMPLE
HAND AUGER B-5
DR
Y
D
E
N
S
I
T
Y
DEPTH
IN
FEET
... WATER TABLE OR SEEPAGE
3/15/21
P. THERIAULTBY:
T2754-22-04 BORING LOGS.GPJ
(B
L
O
W
S
/
F
T
.
)
... SAMPLING UNSUCCESSFUL
CO
N
T
E
N
T
(
%
)
... STANDARD PENETRATION TEST
MATERIAL DESCRIPTION
MO
I
S
T
U
R
E
BU
L
K
DR
/
S
P
T
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.
T2754-22-04
,--
~ -~
~ ,--~
~ -~
~ ,--
~
~
.-1-~l
:-1. 7-l
l~ ·1
:-l rl-
.-1-l "J-~ -l
I]
liiiiJ
I -
-
-
SM
SM
B-6@0-5.0'UNDOCUMENTED FILL (afu)
Silty SAND, damp, light brown, moist; fine to medium sand; some
coarse sand; micaceous
YOUNG ALLUVIAL DEPOSITS (Qya)
Silty SAND, moist, medium dense, brown; fine to medium sand;
micaceous
Total depth 5.0 feet
Groundwater not encountered
Backfilled with cuttings on 3/15/2021
PE
N
E
T
R
A
T
I
O
N
... DRIVE SAMPLE (UNDISTURBED)
HAND AUGERLI
T
H
O
L
O
G
Y
GR
O
U
N
D
W
A
T
E
R
SOIL
CLASS
(USCS)
SAMPLE SYMBOLS
DATE COMPLETED
(P
.
C
.
F
.
)
GEOCON
Figure A-6,
Log of Hand Auger B-6, Page 1 of 1
... DISTURBED OR BAG SAMPLE
0
2
4
SAMPLE
NO.
RE
S
I
S
T
A
N
C
E
66
EQUIPMENT
ELEV. (MSL.)
... CHUNK SAMPLE
HAND AUGER B-6
DR
Y
D
E
N
S
I
T
Y
DEPTH
IN
FEET
... WATER TABLE OR SEEPAGE
3/15/21
P. THERIAULTBY:
T2754-22-04 BORING LOGS.GPJ
(B
L
O
W
S
/
F
T
.
)
... SAMPLING UNSUCCESSFUL
CO
N
T
E
N
T
(
%
)
... STANDARD PENETRATION TEST
MATERIAL DESCRIPTION
MO
I
S
T
U
R
E
BU
L
K
DR
/
S
P
T
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.
T2754-22-04
,--
~ -~
~ ,--~
~ -~
~ ,--
~
~
.-1-~l
:-1. 7-l
l~ ·1
:-l rl-
.-1-l "J-~ -l
I]
liiiiJ
I -
-
-
FIGURE A-7
PROJECT NO. 06796-22-01
a:: BORING B 1 >-UJ ZUJ"' >-,..., g I-<I: Ou• I-" wX DEPTH _J 3 SOIL Hzl-H. 0::'-'
IN SAMPLE 0 □ CLASS ..... <I: LL. (/)LL. =>1-NO. :i:: z ELEV. (MSL.) 12 DATE COMPLETED 4/1/02 <I: I-' z. 1-:z FEET I-::::> (USCS) 0:: CJ) CJ) UJu oow H 0 l:uH8 □. H>-_J a:: EQUIPMENT m A-300 zOO _J >-a.. Oz (.!) W U.110 a:::'-' I:o Q.. 0:: V 0 u
MATERIAL DESCRIPTION -0 ~ --SM ALLUVIUM .... Loose, moist to wet, dark brown, Silty, fine to coarse -2 -SAND with clay ....
Bl-1 ~-~ ,--~✓-} ---------------------------------------4 -SC -Becomes Clayey SAND ,_
... -</,1 --------------------------------------Bl-2 ~~ v/ 5 102.3 27.2 / ,I -Becomes soft, wet, grayish brown, CLAY ... 6 -/; -
/',/ ... -/1/ -/V /1/
,-8 -/V /; -/V /; CL /V /; ,--/V /v -
/ / /v ... 10 -// /V -B1 -3 / / /v -Becomes stiff, gray, Silty CLAY 11 88.0 33.4 --// /',I -// /v // /; -12 -~ //v -
//i; --//v -~ //v
-14 -//11 -//V
I~ //'i,, --/'/v -Becomes very soft, saturated, greenish gray, Silty -Bl-4 //v 2 -16 -~ //v CLAY -/,I
BORING TERMINATED AT 16.5 FEET
No groundwater encountered
Figure A-1, Log of Boring B 1 LCGTS
SAMPLE SYMBOLS 0 ... SAMPLING UNSUCCESSFUL IJ ... STANDA.RD PENETRATION TEST ■ ... DRIVE SAMPLE (UNDISTURBED)
I!§ .•. DISTURBED OR BAG SAMPLE liiiJ ... CHUNK SAMPLE J ... WATER TABLE OR SEEPAGE
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHO\JN 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.
FIGURE A-8
PROJECT NO. 06796-22-01
a:: BORING B 2 >-UJ Zw'"' >-"' (!) I-0 <C Ou• t:;r-w~ OEPTH ...J :I SOIL Hzl-Cl) • a::"'
IN SAMPLE 0 0 CLASS 1-<CIJ.. zu.. :::>1-NO. ::x: z ELEV. (MSL.) 11 DATE COMPLETED 4/1/02 <C1-' w· 1-z FEET I-::) (USCS) o:: en U> □~ U>w H 0 1-H::I ~!z ...J a:: WcnO >-a.. (.!) EQUIPMENT ffi A-300 Zw-' ~ a::!9 O::::v I:o
0 u
MATERIAL DESCRIPTION ... 0
·~ ... -SM ALLUVIUM ...
/ vv ,; Loose, wet, brown, Silty, fine 10 medium SAND with r ... 2 -i~ ~~ I " __ clay ________________________________ ,' ... 8 2-1 ,;
... --Becomes sofl, dark brown, Silty CLAY ... ~ i/!/ ; :t: ... 4 -vv -~ i/!/ ,I=-
... -vv ,I vv ,I -Becomes firm, saturated, dark gray brown, fine to ,-.
82-2 ~~ ,I CL 8 102.5 21.7 ... 6 -~ / coarse Sandy CLAY -,I ... -/ // / ,-. // /,1
-8 -/i/ /'/ .... /!/ /'/ /V /'/ --~~ /',1 ....
/',1 -10 // --------------------------------------82-3 l l 4 --11 ., Becomes loose, Silly, fine 10 coarse SAND with clay -
-12 -: 1 t 1· -SM --J ·l ....
-14 -ti., -. I ~-1· ---82-4 r .11.-,. 7 ... 16 -I i ·1 ...
BORING TERMINATED AT 16.5 FEET
Groundwater encountered at 4 feet
Figure A-2, Log of Boring B 2 LCGTS
SAMPLE SYMBOLS 0 ... SAMPLING UNSUCCESSFUL IJ ... STANDARD PENETRATION TEST ■ ... DRIVE SAMPLE (UNDISTURBED)
l;l§ ... DISTURBED OR BAG SAMPLE liiJ . . . CHUNK SAMPLE ]I'. ... YATER TABLE OR SEEPAGE ..
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE
DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
FIGURE A-9
PROJECT NO 06796-22-01
0:: BORING B 3 >-w zw,-.. >-" (.!) I-
0 (C Ou• l:ii-; w~ DEPTH ...J 3 SOIL ~zt;: o::"'
IN SAMPLE 0 0 CLASS <C (C"
(f),LL. ::::> I-NO. :c z ELEV. (MSL.) 22 DATE COMPLETED 4/1/02 0:: I-(/) ffi . 1-z FEET I-::::> (USCS) I-(/) :::r 0 1~ (/)u.l H 0 wHo ~~ ...J 0:: EQUIPMENT m A-300 Z(f)..J >-·o.. (.!) wWco a::'-' :Co 0.. O::v-0 u
MATERIAL DESCRIPTION -0 0 --ALLUV1UM -Loose, wet, dark brown, Silty, fine to medium SAND -2 -with clay -B3-1 0 SM ,.. --
-4 -:;rt i -
,.. -V / /1..' --------------------------------------B3-2 // /'/ -Becomes firm, saturated, dark blackish gray, Silty 8 89.8 31.4 ,_ 6 -// /i,, -,I/ /v CLAY with abundant organics and many pinholes. ,_ -// /i,, -// /i,, CL ,_ 8 -/ / /i,, -/ / /v
// /v ,_ -~ //ii,, -
//v ,.. 10 -I~ / /y -B3-3 //v -Becomes stiff, dark olive brown with few organics 11 --//y -/Vv
12 ~ /Vii,, - -/Vv -
V !//ii,, --~ V!/v -
-14 -~~~ -//ii,,
B3-4 m
:/!/v 4 - -!/i/y -Becomes soft ,...
/v,, -16 -!/V,, --,,, /I.I
BORING TERMINATED AT 16.5 FEET
Groundwater encountered at 4 feet
Figure A-3, Log of Boring B 3 LCGTS
SAMPLE SYMBOLS 0 ... SAMPL ING UNSUCCESSFUL IJ ... STANDARD PENETRATION TEST ■ ... DRIVE SAMPLE (UNDISTURBED)
§§ ... DISTURBED OR BAG SAMPLE liiiJ ... CHUNK SAMPLE J ... WATER TABLE OR SEEPAGE
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION ANO AT THE
DATE INDICATED, IT IS NOT WARRA~TEO TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS ANO TIMES.
FIGURE A-10
PROJECT NO. 06796-22-01
ffi BORING B 4 >-Zw-'"' >--'"' (.!) I-I--'"' UJ~ 0 <c: Ou• DEPTH _J 3 SOIL Hzl-H, e:: '-'
IN SAMPLE 0 C CLASS I-<J:u. U>u. ~ .... NO. :::c: z ELEV. (MSL.) 22 DATE COMPLETED 4/1/02 <l:1-'-z.
FEET I-::J o::: en en Wu enZ
H 0 (USCS) t-H3 c. HW _J e:: WenO >-a.. ol-
(!) EQUIPMENT ffi A-300 ZUJ_J e:: '-' ;cZ
~e::e 0 C u
MATERIAL DESCRIPTION -0 l/ vv ,I
~ vv I ALLUVIUM --vv ,I -
V Vi/ ,I Soft, wet, dark brown, Silly CLAY ... 2 -m
vv I -B4-1 vv I CL ... -vv ,I -~~ ✓i / -4 -/ vv I -
/ ~~ ,I --I~ -B4-2 vv ,I 16 -6 -!/V ,, -V/ ,, -Becomes stiff, saturated, dark olive brown, Sandy V !/ / ,I SILT --i V v ,, -!/ / y -8 -// y -// y --// /11 -I// /Y
10 V/ 1/,;
I--~ --------------------------------------B4-3 -No recovery 10
I---CL -Becomes firm, dark olive tan, Sandy CLAY ... 12 -,---~ --14 -.% f-
I----------------------------------------84-4 ~ CL 7 -16 --Becomes olive tan to light gray, Silty CLAY -
TRENCH TERMINATED AT 16.5 FEET
Groundwater encountered at 3.5 feet
Figure A-4, Log of Boring B 4 LCGTS
SAMPLE SYMBOLS 0 ... SAMPLING UNSUCCESSFUL IJ ... STANDAIRD PENETRATION TEST ■ ... DRIVE SAMPLE (UNDISTURBED)
~ •.• DISTURBED OR BAG SAMPLE ~ ... CHUNK SAMPLE ! ... WATER TABLE OR SEEPAGE
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHO\JN 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.
FIGURE A-11
PROJECT NO 06796-22-0 I
0:: BORING B 5 >-LU zl.U,-,.. >-" t!) I-0 a: Ou• I-'"' w~ DEPTH ...J 3 SOIL Hzl-H . Q:: V
IN SAMPLE 0 0 CLASS I-(Cl&.. (J)LL =>1-:I: z ELEV. (MSL.) 25 DA TE COMPLETED 4/J /02 <I:1-' ffi . NO. Ct::(/)(/) 1-z FEET I:; ::::, (USCS) a~ (/)UJ 0 I-H3 H1-...J a:: LJJ(/)0 >-a. Oz t!) EQUIPMENT m. A-300 ffi w~ o::'-' :Co
Q. a::'-" a u
MATERIAL DESCRIPTION ,-0 r1.; ,--SC ALLUVIUM -B5-1 v<// Loose, wet, light brown, Clayey SAND -2 ---------------------------------------... -~ -Becomes soft, dark brown, Silty CLAY -
-4 --
--~ I -B5-2 CL -No recovery 11 -6 --
--~ -
-8 --
---
... 10 -z -B5-3 -No recovery 23 --. -~ -
~✓-~ --------------------------------------... 12 -B5-4 SC Loose, saruratcd, tan, brown, Clayey, fine to coarse -8
✓ ✓·I; . ... -) / ·,~ I . __ SAND ______________________________ , I -
, ; ,I/ -Becomes firm, saruratcd, ligh1 gray and tan, Sandy ... 14 -• ./LI -,) _, LI ML SILT with clay
,--r~ /;), -85-5 /I;'. 9 · vii -16 -_;,, ·1; -
BORING TERMINATED AT 16.5 FEET
Groundwater at 5 feet
Figure A-5, Log of Boring B 5 LCGTS
SAMPLE SYMBOLS 0 ... SAMPLING UNSUCCESSFUL IJ ... STANDARD PENETRATION TEST ■ ... DRIVE SAMPLE (UNDISTURBED)
ffli ... DISTURBED OR BAG SAMPLE ~ -•• CHUNK SAMPLE ~ ••• \JATER TABLE OR SEEPAGE ...
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHO',IN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE
DATE INDICATED. IT IS NOT ~ARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
FIGURE A-12
PROJECT NO 06796-22-0 I
0:: BORING B 6 >-IJJ ZIJJ" >-" (.!) I-0 <J: Ou • I-" w.-: DEPTH ...J :::t SOIL ~zt H . a::"'
IN SAMPLE 0 a CLASS <I: <I:' (/)u.. =>1-NO. ::c z ELEV. (MSL.) 32 DATE COMPLETED 4/1/02 o:: I-en r5 . 1-z FEET l=i ::::, (USCS) 1-(/):::t a~ <nw 0 wHo HI-...J a:: EQUIPMENT IR A-300 Z(l)...J >-Q. Oz (.!) wWa::, o::v l:o Q. 0::...., a u
MA TERlAL DESCRJPTION -0 :-1. 1 ·l FILL --ll-1 SM Loose, wet, dark brown, Silty, fine lo medium SAND -86-1 -2 -// /i,, with some clay
/,I /y ALLUVIUM --/ ,I /i,, I -/ ,I /y Soft, wet, dark olive brown, Silty CLAY -4 -// /it CL -/ ,I /v --i/i/ /
1 ✓· '·/---------------------------------------86-2 1/;; -Becomes loose, dark gray brown, Clayey, fine to 10 111.4 19.9 -6 --{// coarse SAND with silt --[(// -SC .... 8 -//. -v://
0--~/}. -
-10 -I {// -86-3 ,. __ -!-!S~l_b~o~E,_q>~~eJ '!!l~ ~ale! _________________ ,· I '7 1('1 .., 'lC: A
--
I~ -Becomes stiff, wcl, light olive tan and green, Sandy --12 -CLAY -CL - -~ -
-14 -----86-4 [0 16 -16 ---Becomes light olive green and gr.ay. fine to coarse
SAND I
BORING TERMINATED AT 16.5 FEET
Groundwater al 3.5 feet
Figure A-6, Log of Boring B 6 LCGTS
SAMPLE SYMBOLS 0 ... SAMPLING UNSUCCESSFUL IJ ... STANDARD PENETRATION TEST ■ ... DRIVE SAMPLE (UNDISTURBED)
~ ••. DISTURBED OR BAG SAMPLE ~ -.. CHUNK SAMPLE ~ ... WATER TABLE OR SEEPAGE ....
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHO\.IN 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 LOCAT IONS AND TIMES.
FIGURE A-13
PROJECT NO. 06796-22-0J
Q:: BORING B 7 >-IJJ Zw" >-,... (.!) I-0 <t Ou• ~~ wX DEPTH SAMPLE ...J :I SOIL Hzl-Q::'"'
IN 0 0 CLASS I-<CLL zLL =>,-NO. ::c z ELEV. (MSL.) 44 DATE COMPLETED 4/1/02 <Cl-' w· 1-z FEET l::i ::) (USCS) a::(/)(/) a~ (/) UJ 0 I-H3 H,-....J Q::
EQUIPMENT
W(l)O >-0.. Oz t!) fR A-300 Zw....J Q::'-' :Co ~o::~ 0 u
MATERIAL DESCRIPTION ... 0 ~ ... -SM FILL I-fil Loose, wet, light tan brown, Silty , fine to medium ... 2 -SAND with clay I-
87-1 v·/·/: f---~---) ALLUVIUM ....
I-4 -t// SC Loose, moist to slightly wet, dark brown, Clayey, fine -
;, /./ to coarse SAND ... ---------------------------------------87-2 I~ -Becomes stiff, light tan brown, fine 10 medjum 18 102.7 23.2 ... 6 -I-Sandy CLAY
--I-
-8 -z ? CL ....
--½ ,-
-10 ---------------------------------------87-3 ~~ /'/ 26 // -Becomes very stiff, saturated, light olive gray and --~~ /'/ ....
// green, Silty CLAY -12 -/V /i,; ,-/V /i,; CL --/V /i,; ,... ~~ //
14 /i,; --/V /y -
/V /y ... -1 <-.M --------------------------------------87-4 I 'l
~,t . -Becomes medium dense, saturated, light tan, Silty, i
f--16 -ML I fine to medium SAND ,-
I ------------------------------------, Becomes stiff, wet, olive tan, Clayey SILT
BORING TERMINATED AT 16.5 FEET
Groundwater at 8 feel
Figure A-7, Log of Boring B 7 LCGTS
SAMPLE SYMBOLS 0 ... SAMPLING UNSUCCESSFUL IJ ... STANDARD PENETRATION TEST ■ ... DRIVE SAMPLE (UNDISTURBED)
~ .•. DISTURBED OR BAG SAMPLE ~ -.. CHUNK SAMPLE ~ ..• \./ATER TABLE OR SEEPAGE -
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHO\.IN 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.
FIGURE A-14
PROJECT NO 06796-22-01
0:: BORING B 8 >-IJJ ZIJJ"' §-; ,... (.!) I-0 <t Ou . w:-: DEPTH SAMPLE ...J ::I SOIL Hzf-o::'-'
IN 0 □ CLASS f-<CIJ.. zLL =>1-NO. :c z ELEV. (MSL.) 46 DATE COMPLETED 4/1/02 <tt-" IJ.J • t-z FEET t-=> (USCS) O::u,U> 0~ (/)UJ H 0 l:uH5 H1-...J 0:: EQUIPMENT IR A-300 zU>...J >-a.. Oz (.!) w IJJtO 0::'"' Eo a.. 0::...., 0 u
MATERIAL DESCRIPTION -0 --.1: 1 :1· SM FILL -B8-I Loose, moist, light tan, brown, Silly, fine 10 medium -2 -V vv LI \ SAND / ....
II
/V y /V I ALLUVIUM --/V I ~ I-/V i,,_ Soft, wet, dark brown, Silly CLAY -4 -/V y --/1/ I CL ... -/V I ~~ i,, ...
B8-2 y -Becomes stiff, wet, dark tan and brown 11 92.5 30.5 -6 -~ I ...
/V I --/!,.I I ,-~ vv
-8 -/V I vv I ,-
vv I --~ vv I ,-vv I -10 -//
1-:]:y::· --------------------------------------B8-3 16 108.0 23.0 - --Becomes medium dense, saturated, light tan brown, ...
SM Silty, fine to medium SAND with trace clay -12 -:·1 :-,. ...
--:1-·l ,-
-14 -:r.t,. ,-
--v~~ ------------------------------------ -B8-4 ~ :; CL -Becomes firm, wet, light brownish gray, Silly CLAY 6 -16 --
BORING TERMINATED AT 16.5 FEET
Groundwater encountered at 3.5 feet
Figure A-8, Log of Boring B 8 LCGTS
SAMPLE SYMBOLS D ... SAMPL ING UNSUCCESSFUL IJ ... STANDARD PENETRATION TEST ■ ... DRIVE SAMPLE (UNDISTURBED)
I!§ ... OISlURBEO OR BAG SAMPLE ~ ..• CHUNK SAMPLE J ... WATER TABLE OR SEEPAGE
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHQ',/N HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION ANO AT THE
DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS ANO TIMES.
APPENDIX B
Geocon Project No. T2754-22-04 -B- April 15, 2021
APPENDIX B
LABORATORY TESTING
We performed laboratory tests in accordance with current generally accepted test methods of ASTM
International (ASTM) or other suggested procedures. We analyzed selected soil samples for in-situ
density and moisture content, maximum dry density and optimum moisture content, water-soluble
sulfate, R-value, and direct shear strength. The results of the laboratory tests are presented on
Figures B-1 and B-2. Results of previous laboratory test results (Geocon, 2002) are presented on
Figures B-3 and B-4. The in-place dry density and moisture content of the samples tested are
presented on the boring logs in Appendix A.
LABORATORY TEST RESULTS
CHAMPIONS COURSE RENAVATIONS
OMNI LA COSTA RESORT & SPA
2100 COTSA DEL MAR ROAD
CARLSBAD, CALIFORNIA
PST APRIL 2021 PROJECT NO. T2754-22-04 FIG B-1
X
SUMMARY OF LABORATORY MAXIMUM DRY DENSITY
AND OPTIMUM MOISTURE CONTENT TEST RESULTS
ASTM D1557
Sample No. Description
Maximum
Dry Density
(pcf)
Optimum
Moisture Content
(% of dry wt.)
B-2 @ 0-5’ Sandy CLAY (CL), dark brown 119.5 8.5
SUMMARY OF WATER-SOLUBLE SULFATE TEST RESULTS
Sample No. Sulfate Content (%)
B-5 @ 0-5’ 0.100
B-3 @ 0-5’ 1.390
Water-soluble sulfate determined by California Test 417.
SUMMARY OF LABORATORY R-VALUE TEST RESULTS
ASTM D2844
Sample No. R-Value
B-4 @ 0-5’ 7
GEOCON
W E S T, I N C.
GEOTECHNICAL ENVIRONMENTAL MATERIALS
41571 CORNING PLACE. SUITE 101. MURRIETA. CA 92562-7065
PHONE 951-304-2300 FAX 951-304-2392
I I I I
Project No.: T2754-22-04
2.98
Boring No. B2 Normal Strest (kip/ft2) 1 3 5
Sample No. B2@0-5 Peak Shear Stress (kip/ft²) 0.71 1.91
0.05
Depth (ft) 0-5 Shear Stress @ End of Test (ksf) 0.71 1.87 2.95
Sample Type:Ring Deformation Rate (in./min.)0.05 0.05
Soil Identification:Initial Sample Height (in.)1.0 1.0 1.0
Clayey Sand (SC) - dark brown Ring Inside Diameter (in.)2.375 2.375 2.375
Initial Moisture Content (%)8.6 8.6 8.6
Strength Parameters Initial Dry Density (pcf)108.0 108.0 108.1
41.2 41.5
Peak 163 29.6 Soil Height Before Shearing (in.) 1.2 1.2 1.2
C (psf)Initial Degree of Saturation (%) 41.3
Ultimate 161 29.3 Final Moisture Content (%) 17.7 12.7
DIRECT SHEAR TEST RESULTS CHAMPIONS COURSE RENOVATIONS
OMNI LA COSTA RESOR T & SPA
CARLSBAD, CALIFORNIAConsolidated Drained ASTM D-3080
Checked by:
15.8
Apr 21 Figure B2
0.0
1.0
2.0
3.0
4.0
5.0
0.0 1.0 2.0 3.0 4.0 5.0
Sh
e
a
r
S
t
r
e
s
s
(
k
s
f
)
Normal Stress (ksf)
I/'
/ ---
V v ·
/
-
/ V
• ■ ...
0 □ ~
r ~
GEOCON
FIGURE B-3
APPENDIX B
LABORATORY TESTING
Laboratory tests were performed in accordance wi th generally accepted test methods of the American
Society for Testing and Materials (ASTM) or other suggested procedures. Selected samples were
tested for their in-situ dry density and moisture content, compaction characteristics, direct shear
strength, water-soluble sulfate content, sieve analysis, pH and resistivity test. Results of the
laboratory tests are presented below. In -situ dry density and moisture content arc presented on the
boring logs in Appendix A.
Sample
o.
B 1-J
B7-I
Sample
No.
81-2
B6-2
B8-3
TABLE B-1
SUMMARY OF LABORATORY MAXIMUM DRY DENSITY ANO
OPTIMUM MOISTURE CONTENT TEST RESULTS
ASTM D 1557-00
Maximum Dry O ptimum
Description Density (pd) Moisture Content
(% d ry wt.)
Dark brown, Silty fine to coarse SAND 127.4 10.J with clay
Dark brown, Silty, fine to medium SAND 126.6 9.9 with clay
TABLE B-11
SUMMARY OF LABORATORY DIRECT SHEAR TEST RESULTS
ASTM D 3080-98
Dry Density Moisture Content Unit Cohesion Angle of Shear
(pc() (%) (ps() Resistance (degrees)
102.3 27.2 450 28
111.4 19.9 280 38
108.0 23.0 500 38
Projecl No. 06796-22-0 L -B-1 -Apnl 30, 2002
Revised July 17, 2002
FIGURE B-4
TABLE 8-111
SUMMARY OF LABORATORY WATER-SOLUBLE SULFATE TEST RESULTS
CALIFORNIA TEST NO. 417
Sample No. Water-Soluble Sulfate(%) Sulfate Exposure
(UBC Table 19-A-4)
Bl-1 0.196 I "Moderate"
B8-1 0.174 "Moderale"
TABLE B-IV
SUMMARY OF LABORATORY SIEVE ANALYSIS TEST RESULTS
ASTM D 1140
Sieve Analysis ASTM D-42.2 Sample No. 82-3 Sample o. B4-2
(Sieve Size) (% Passing) (% Passing)
No.4 100 100
No. 8 96 100
No. 16 91 99
No. 30 84 98
No. 50 75 92
No. 100 58 66
No. 200 48 52
TABLE B-V
SUMMARY OF LABORATORY RESISTIVITY
AND POTENTIAL OF HYDROGEN (pH) TEST RESULTS
CALIFORNIA TEST NO. 643
Sample No. Resistance (ohm cm}
B8-1 427
P rOJCCl No. 06796-22-0 I -B-2 -
pH
8.0
Apnl 30. 2002
Revised July 17. 2002
APPENDIX C
Geocon Project No. T2754-22-04 - C - April 15, 2021
APPENDIX C
RECOMMENDED GRADING SPECIFICATIONS
FOR
CHAMPIONS COUSRE RENOVATIONS
OMNI LA COSTA RESOR T & SPA
2100 COSTA DEL MAR ROAD
CARLSBAD, CALIFORNIA
PROJECT NO. T2754-22-04
GI rev. 07/2015
RECOMMENDED GRADING SPECIFICATIONS
1. GENERAL
1.1 These Recommended Grading Specifications shall be used in conjunction with the
Geotechnical Report for the project prepared by Geocon. The recommendations contained
in the text of the Geotechnical Report are a part of the earthwork and grading specifications
and shall supersede the provisions contained hereinafter in the case of conflict.
1.2 Prior to the commencement of grading, a geotechnical consultant (Consultant) shall be
employed for the purpose of observing earthwork procedures and testing the fills for
substantial conformance with the recommendations of the Geotechnical Report and these
specifications. The Consultant should provide adequate testing and observation services so
that they may assess whether, in their opinion, the work was performed in substantial
conformance with these specifications. It shall be the responsibility of the Contractor to
assist the Consultant and keep them apprised of work schedules and changes so that
personnel may be scheduled accordingly.
1.3 It shall be the sole responsibility of the Contractor to provide adequate equipment and
methods to accomplish the work in accordance with applicable grading codes or agency
ordinances, these specifications and the approved grading plans. If, in the opinion of the
Consultant, unsatisfactory conditions such as questionable soil materials, poor moisture
condition, inadequate compaction, and/or adverse weather result in a quality of work not in
conformance with these specifications, the Consultant will be empowered to reject the
work and recommend to the Owner that grading be stopped until the unacceptable
conditions are corrected.
2. DEFINITIONS
2.1 Owner shall refer to the owner of the property or the entity on whose behalf the grading
work is being performed and who has contracted with the Contractor to have grading
performed.
2.2 Contractor shall refer to the Contractor performing the site grading work.
2.3 Civil Engineer or Engineer of Work shall refer to the California licensed Civil Engineer
or consulting firm responsible for preparation of the grading plans, surveying and verifying
as-graded topography.
2.4 Consultant shall refer to the soil engineering and engineering geology consulting firm
retained to provide geotechnical services for the project.
GI rev. 07/2015
2.5 Soil Engineer shall refer to a California licensed Civil Engineer retained by the Owner,
who is experienced in the practice of geotechnical engineering. The Soil Engineer shall be
responsible for having qualified representatives on-site to observe and test the Contractor's
work for conformance with these specifications.
2.6 Engineering Geologist shall refer to a California licensed Engineering Geologist retained
by the Owner to provide geologic observations and recommendations during the site
grading.
2.7 Geotechnical Report shall refer to a soil report (including all addenda) which may include
a geologic reconnaissance or geologic investigation that was prepared specifically for the
development of the project for which these Recommended Grading Specifications are
intended to apply.
3. MATERIALS
3.1 Materials for compacted fill shall consist of any soil excavated from the cut areas or
imported to the site that, in the opinion of the Consultant, is suitable for use in construction
of fills. In general, fill materials can be classified as soil fills, soil-rock fills or rock fills, as
defined below.
3.1.1 Soil fills are defined as fills containing no rocks or hard lumps greater than
12 inches in maximum dimension and containing at least 40 percent by weight of
material smaller than ¾ inch in size.
3.1.2 Soil-rock fills are defined as fills containing no rocks or hard lumps larger than
4 feet in maximum dimension and containing a sufficient matrix of soil fill to allow
for proper compaction of soil fill around the rock fragments or hard lumps as
specified in Paragraph 6.2. Oversize rock is defined as material greater than
12 inches.
3.1.3 Rock fills are defined as fills containing no rocks or hard lumps larger than 3 feet
in maximum dimension and containing little or no fines. Fines are defined as
material smaller than ¾ inch in maximum dimension. The quantity of fines shall be
less than approximately 20 percent of the rock fill quantity.
3.2 Material of a perishable, spongy, or otherwise unsuitable nature as determined by the
Consultant shall not be used in fills.
3.3 Materials used for fill, either imported or on-site, shall not contain hazardous materials as
defined by the California Code of Regulations, Title 22, Division 4, Chapter 30, Articles 9
GI rev. 07/2015
and 10; 40CFR; and any other applicable local, state or federal laws. The Consultant shall
not be responsible for the identification or analysis of the potential presence of hazardous
materials. However, if observations, odors or soil discoloration cause Consultant to suspect
the presence of hazardous materials, the Consultant may request from the Owner the
termination of grading operations within the affected area. Prior to resuming grading
operations, the Owner shall provide a written report to the Consultant indicating that the
suspected materials are not hazardous as defined by applicable laws and regulations.
3.4 The outer 15 feet of soil-rock fill slopes, measured horizontally, should be composed of
properly compacted soil fill materials approved by the Consultant. Rock fill may extend to
the slope face, provided that the slope is not steeper than 2:1 (horizontal:vertical) and a soil
layer no thicker than 12 inches is track-walked onto the face for landscaping purposes. This
procedure may be utilized provided it is acceptable to the governing agency, Owner and
Consultant.
3.5 Samples of soil materials to be used for fill should be tested in the laboratory by the
Consultant to determine the maximum density, optimum moisture content, and, where
appropriate, shear strength, expansion, and gradation characteristics of the soil.
3.6 During grading, soil or groundwater conditions other than those identified in the
Geotechnical Report may be encountered by the Contractor. The Consultant shall be
notified immediately to evaluate the significance of the unanticipated condition
4. CLEARING AND PREPARING AREAS TO BE FILLED
4.1 Areas to be excavated and filled shall be cleared and grubbed. Clearing shall consist of
complete removal above the ground surface of trees, stumps, brush, vegetation, man-made
structures, and similar debris. Grubbing shall consist of removal of stumps, roots, buried
logs and other unsuitable material and shall be performed in areas to be graded. Roots and
other projections exceeding 1½ inches in diameter shall be removed to a depth of 3 feet
below the surface of the ground. Borrow areas shall be grubbed to the extent necessary to
provide suitable fill materials.
4.2 Asphalt pavement material removed during clearing operations should be properly
disposed at an approved off-site facility or in an acceptable area of the project evaluated by
Geocon and the property owner. Concrete fragments that are free of reinforcing steel may
be placed in fills, provided they are placed in accordance with Section 6.2 or 6.3 of this
document.
GI rev. 07/2015
4.3 After clearing and grubbing of organic matter and other unsuitable material, loose or
porous soils shall be removed to the depth recommended in the Geotechnical Report. The
depth of removal and compaction should be observed and approved by a representative of
the Consultant. The exposed surface shall then be plowed or scarified to a minimum depth
of 6 inches and until the surface is free from uneven features that would tend to prevent
uniform compaction by the equipment to be used.
4.4 Where the slope ratio of the original ground is steeper than 5:1 (horizontal:vertical), or
where recommended by the Consultant, the original ground should be benched in
accordance with the following illustration.
TYPICAL BENCHING DETAIL
Remove All
Unsuitable Material
As Recommended By
Consultant
Finish Grade Original Ground
Finish Slope Surface
Slope To Be Such That
Sloughing Or Sliding
Does Not Occur Varies
“B”
See Note 1
No Scale
See Note 2
1
2
DETAIL NOTES: (1) Key width "B" should be a minimum of 10 feet, or sufficiently wide to permit complete coverage with the compaction equipment used. The base of the key should be graded horizontal, or inclined slightly into the natural slope.
(2) The outside of the key should be below the topsoil or unsuitable surficial material and at least 2 feet into dense formational material. Where hard rock is exposed in the bottom of the key, the depth and configuration of the key may be modified as approved by the Consultant.
4.5 After areas to receive fill have been cleared and scarified, the surface should be moisture
conditioned to achieve the proper moisture content, and compacted as recommended in
Section 6 of these specifications.
GI rev. 07/2015
5. COMPACTION EQUIPMENT
5.1 Compaction of soil or soil-rock fill shall be accomplished by sheepsfoot or segmented-steel
wheeled rollers, vibratory rollers, multiple-wheel pneumatic-tired rollers, or other types of
acceptable compaction equipment. Equipment shall be of such a design that it will be
capable of compacting the soil or soil-rock fill to the specified relative compaction at the
specified moisture content.
5.2 Compaction of rock fills shall be performed in accordance with Section 6.3.
6. PLACING, SPREADING AND COMPACTION OF FILL MATERIAL
6.1 Soil fill, as defined in Paragraph 3.1.1, shall be placed by the Contractor in accordance with
the following recommendations:
6.1.1 Soil fill shall be placed by the Contractor in layers that, when compacted, should
generally not exceed 8 inches. Each layer shall be spread evenly and shall be
thoroughly mixed during spreading to obtain uniformity of material and moisture
in each layer. The entire fill shall be constructed as a unit in nearly level lifts. Rock
materials greater than 12 inches in maximum dimension shall be placed in
accordance with Section 6.2 or 6.3 of these specifications.
6.1.2 In general, the soil fill shall be compacted at a moisture content at or above the
optimum moisture content as determined by ASTM D 1557.
6.1.3 When the moisture content of soil fill is below that specified by the Consultant,
water shall be added by the Contractor until the moisture content is in the range
specified.
6.1.4 When the moisture content of the soil fill is above the range specified by the
Consultant or too wet to achieve proper compaction, the soil fill shall be aerated by
the Contractor by blading/mixing, or other satisfactory methods until the moisture
content is within the range specified.
6.1.5 After each layer has been placed, mixed, and spread evenly, it shall be thoroughly
compacted by the Contractor to a relative compaction of at least 90 percent.
Relative compaction is defined as the ratio (expressed in percent) of the in-place
dry density of the compacted fill to the maximum laboratory dry density as
determined in accordance with ASTM D 1557. Compaction shall be continuous
over the entire area, and compaction equipment shall make sufficient passes so that
the specified minimum relative compaction has been achieved throughout the
entire fill.
GI rev. 07/2015
6.1.6 Where practical, soils having an Expansion Index greater than 50 should be placed
at least 3 feet below finish pad grade and should be compacted at a moisture
content generally 2 to 4 percent greater than the optimum moisture content for the
material.
6.1.7 Properly compacted soil fill shall extend to the design surface of fill slopes. To
achieve proper compaction, it is recommended that fill slopes be over-built by at
least 3 feet and then cut to the design grade. This procedure is considered
preferable to track-walking of slopes, as described in the following paragraph.
6.1.8 As an alternative to over-building of slopes, slope faces may be back-rolled with a
heavy-duty loaded sheepsfoot or vibratory roller at maximum 4-foot fill height
intervals. Upon completion, slopes should then be track-walked with a D-8 dozer
or similar equipment, such that a dozer track covers all slope surfaces at least
twice.
6.2 Soil-rock fill, as defined in Paragraph 3.1.2, shall be placed by the Contractor in accordance
with the following recommendations:
6.2.1 Rocks larger than 12 inches but less than 4 feet in maximum dimension may be
incorporated into the compacted soil fill, but shall be limited to the area measured
15 feet minimum horizontally from the slope face and 5 feet below finish grade or
3 feet below the deepest utility, whichever is deeper.
6.2.2 Rocks or rock fragments up to 4 feet in maximum dimension may either be
individually placed or placed in windrows. Under certain conditions, rocks or rock
fragments up to 10 feet in maximum dimension may be placed using similar
methods. The acceptability of placing rock materials greater than 4 feet in
maximum dimension shall be evaluated during grading as specific cases arise and
shall be approved by the Consultant prior to placement.
6.2.3 For individual placement, sufficient space shall be provided between rocks to allow
for passage of compaction equipment.
6.2.4 For windrow placement, the rocks should be placed in trenches excavated in
properly compacted soil fill. Trenches should be approximately 5 feet wide and
4 feet deep in maximum dimension. The voids around and beneath rocks should be
filled with approved granular soil having a Sand Equivalent of 30 or greater and
should be compacted by flooding. Windrows may also be placed utilizing an
"open-face" method in lieu of the trench procedure, however, this method should
first be approved by the Consultant.
GI rev. 07/2015
6.2.5 Windrows should generally be parallel to each other and may be placed either
parallel to or perpendicular to the face of the slope depending on the site geometry.
The minimum horizontal spacing for windrows shall be 12 feet center-to-center
with a 5-foot stagger or offset from lower courses to next overlying course. The
minimum vertical spacing between windrow courses shall be 2 feet from the top of
a lower windrow to the bottom of the next higher windrow.
6.2.6 Rock placement, fill placement and flooding of approved granular soil in the
windrows should be continuously observed by the Consultant.
6.3 Rock fills, as defined in Section 3.1.3, shall be placed by the Contractor in accordance with
the following recommendations:
6.3.1 The base of the rock fill shall be placed on a sloping surface (minimum slope of 2
percent). The surface shall slope toward suitable subdrainage outlet facilities. The
rock fills shall be provided with subdrains during construction so that a hydrostatic
pressure buildup does not develop. The subdrains shall be permanently connected
to controlled drainage facilities to control post-construction infiltration of water.
6.3.2 Rock fills shall be placed in lifts not exceeding 3 feet. Placement shall be by rock
trucks traversing previously placed lifts and dumping at the edge of the currently
placed lift. Spreading of the rock fill shall be by dozer to facilitate seating of the
rock. The rock fill shall be watered heavily during placement. Watering shall
consist of water trucks traversing in front of the current rock lift face and spraying
water continuously during rock placement. Compaction equipment with
compactive energy comparable to or greater than that of a 20-ton steel vibratory
roller or other compaction equipment providing suitable energy to achieve the
required compaction or deflection as recommended in Paragraph 6.3.3 shall be
utilized. The number of passes to be made should be determined as described in
Paragraph 6.3.3. Once a rock fill lift has been covered with soil fill, no additional
rock fill lifts will be permitted over the soil fill.
6.3.3 Plate bearing tests, in accordance with ASTM D 1196, may be performed in both
the compacted soil fill and in the rock fill to aid in determining the required
minimum number of passes of the compaction equipment. If performed, a
minimum of three plate bearing tests should be performed in the properly
compacted soil fill (minimum relative compaction of 90 percent). Plate bearing
tests shall then be performed on areas of rock fill having two passes, four passes
and six passes of the compaction equipment, respectively. The number of passes
required for the rock fill shall be determined by comparing the results of the plate
bearing tests for the soil fill and the rock fill and by evaluating the deflection
GI rev. 07/2015
variation with number of passes. The required number of passes of the compaction
equipment will be performed as necessary until the plate bearing deflections are
equal to or less than that determined for the properly compacted soil fill. In no case
will the required number of passes be less than two.
6.3.4 A representative of the Consultant should be present during rock fill operations to
observe that the minimum number of “passes” have been obtained, that water is
being properly applied and that specified procedures are being followed. The actual
number of plate bearing tests will be determined by the Consultant during grading.
6.3.5 Test pits shall be excavated by the Contractor so that the Consultant can state that,
in their opinion, sufficient water is present and that voids between large rocks are
properly filled with smaller rock material. In-place density testing will not be
required in the rock fills.
6.3.6 To reduce the potential for “piping” of fines into the rock fill from overlying soil
fill material, a 2-foot layer of graded filter material shall be placed above the
uppermost lift of rock fill. The need to place graded filter material below the rock
should be determined by the Consultant prior to commencing grading. The
gradation of the graded filter material will be determined at the time the rock fill is
being excavated. Materials typical of the rock fill should be submitted to the
Consultant in a timely manner, to allow design of the graded filter prior to the
commencement of rock fill placement.
6.3.7 Rock fill placement should be continuously observed during placement by the
Consultant.
7. SUBDRAINS
7.1 The geologic units on the site may have permeability characteristics and/or fracture
systems that could be susceptible under certain conditions to seepage. The use of canyon
subdrains may be necessary to mitigate the potential for adverse impacts associated with
seepage conditions. Canyon subdrains with lengths in excess of 500 feet or extensions of
existing offsite subdrains should use 8-inch-diameter pipes. Canyon subdrains less than 500
feet in length should use 6-inch-diameter pipes.
GI rev. 07/2015
TYPICAL CANYON DRAIN DETAIL
7.2 Slope drains within stability fill keyways should use 4-inch-diameter (or lager) pipes.
NATURAL GROUND _,,,,/.,,---
SEE DETAL BELOW
NOTES:
1 ...... 8-lNCH DIAMETER, SCHEDULE 80 PVC PERFORATED PIPE FOR FILLS
IN EXCESS OF 100-FEET IN DEPTH OR A PIPE LENGTH OF LONGER THAN 500 FEET.
2 ...... 6-INCH DIAMETER, SCHEDULE 40 PVC PERFORATED PIPE FOR FILLS
LESS THAN 100-FEET IN DEPTH OR A PIPE LENGTH SHORTER THAN 500 FEET.
.,
.,,.,,.,,
.,...,,.,,,,,..,,,.
BEDROCK
NOTE: FINAL 20' OF PIPE AT Olm.ET
SHALL BE NON-PERFORATED.
9 CUBIC FEET I FOOT OF OPEN
GRADED GRAVEL SURROUNDED BY
MIRAFI 140NC (OR EQUIVALENl)
FILTER FABRIC
NO SCALE
GI rev. 07/2015
TYPICAL STABILITY FILL DETAIL
7.3 The actual subdrain locations will be evaluated in the field during the remedial grading
operations. Additional drains may be necessary depending on the conditions observed and
the requirements of the local regulatory agencies. Appropriate subdrain outlets should be
evaluated prior to finalizing 40-scale grading plans.
7.4 Rock fill or soil-rock fill areas may require subdrains along their down-slope perimeters to
mitigate the potential for buildup of water from construction or landscape irrigation. The
subdrains should be at least 6-inch-diameter pipes encapsulated in gravel and filter fabric.
Rock fill drains should be constructed using the same requirements as canyon subdrains.
DETAIL
FORMA TIONAL MATERIAL
1 ..•.. EXCAVATE BACKCUT AT 1:1 INCUNATION (Ui'LESS OTHERWISE NOTED~
2 .... .BASE OF STABILITY FILL TO BE 3 FEET INTO FORMATIONAL MATERIAL, SLOPING A MINIMUM 5')1, INTO SLOPE.
3 ..... STABIUTY FLL TO BE COMF'OSED OF PROPEFa. Y COMPACTED GRANLA.AR SOIL.
4 ..... CHIMNEY DRAINS TO BE APPROVED PREFABRICATED CHIMNEY DRAIN PANas (MIRADRAIN G200N OR EQUIVALENTI
SPACED AF'PROXIMATELY 20 FEET CENTER TO CENTER ANO 4 FEETWIDE. CLOSER SPACING MAY BE REQUIRED IF
SEEPAGE IS ENCOUNTERED.
5 ..... Fll TER MATERIAL TO BE 31'4-INCH, OPEN-GRADED CRUSHED ROCK ENCLOSED IN APPROVED FL TER FABAIC (MIRAFl 140NCi
6 ..... COLLECTOR PIPE TO BE 4-INCH MINIMUM DIAMETER, PERFORATED, THICK-WAULED PVC SCI-IEDULE 40 OR
EQUIVALENT, AND SI.OPEC TO CRAIN AT 1 PERCENT t.lNMUM TO APPROVED ounET.
NO SCALE
GI rev. 07/2015
7.5 Prior to outletting, the final 20-foot segment of a subdrain that will not be extended during
future development should consist of non-perforated drainpipe. At the non-perforated/
perforated interface, a seepage cutoff wall should be constructed on the downslope side of
the pipe.
TYPICAL CUT OFF WALL DETAIL
7.6 Subdrains that discharge into a natural drainage course or open space area should be
provided with a permanent headwall structure.
FRONT VIEW
SIDE VIEW
'
CONCRETE
CUT-OFF WAIJ.
CONCRETE
CUT-OFF WAIJ.
SOLID SUBDRAJN PIPE
/
NO SCALE
6" MIN. (TYP)
PE•RFoRATED SUBORA1N PIPE . . . . .
6" MIN. (TYP)
NO SCALE
GI rev. 07/2015
TYPICAL HEADWALL DETAIL
7.7 The final grading plans should show the location of the proposed subdrains. After
completion of remedial excavations and subdrain installation, the project civil engineer
should survey the drain locations and prepare an “as-built” map showing the drain
locations. The final outlet and connection locations should be determined during grading
operations. Subdrains that will be extended on adjacent projects after grading can be placed
on formational material and a vertical riser should be placed at the end of the subdrain. The
grading contractor should consider videoing the subdrains shortly after burial to check
proper installation and functionality. The contractor is responsible for the performance of
the drains.
FRONT VIEW
SIDE VIEW
8"0R8"
SUlDRAIN
CONCRETE
HEADWALL
8"0RB"
SUBORAIN
~ 24•
NOTE: HEADWALL SHOULD ounET AT TOE OF FILL SLOPE
OR INTO CONTROLLED SURFACE DRAINAGE
-::--:.-: :.r4~---. :~ .
NO SCALE
12"
NO SCALE
GI rev. 07/2015
8. OBSERVATION AND TESTING
8.1 The Consultant shall be the Owner’s representative to observe and perform tests during
clearing, grubbing, filling, and compaction operations. In general, no more than 2 feet in
vertical elevation of soil or soil-rock fill should be placed without at least one field density
test being performed within that interval. In addition, a minimum of one field density test
should be performed for every 2,000 cubic yards of soil or soil-rock fill placed and
compacted.
8.2 The Consultant should perform a sufficient distribution of field density tests of the
compacted soil or soil-rock fill to provide a basis for expressing an opinion whether the fill
material is compacted as specified. Density tests shall be performed in the compacted
materials below any disturbed surface. When these tests indicate that the density of any
layer of fill or portion thereof is below that specified, the particular layer or areas
represented by the test shall be reworked until the specified density has been achieved.
8.3 During placement of rock fill, the Consultant should observe that the minimum number of
passes have been obtained per the criteria discussed in Section 6.3.3. The Consultant
should request the excavation of observation pits and may perform plate bearing tests on
the placed rock fills. The observation pits will be excavated to provide a basis for
expressing an opinion as to whether the rock fill is properly seated and sufficient moisture
has been applied to the material. When observations indicate that a layer of rock fill or any
portion thereof is below that specified, the affected layer or area shall be reworked until the
rock fill has been adequately seated and sufficient moisture applied.
8.4 A settlement monitoring program designed by the Consultant may be conducted in areas of
rock fill placement. The specific design of the monitoring program shall be as
recommended in the Conclusions and Recommendations section of the project
Geotechnical Report or in the final report of testing and observation services performed
during grading.
8.5 We should observe the placement of subdrains, to check that the drainage devices have
been placed and constructed in substantial conformance with project specifications.
8.6 Testing procedures shall conform to the following Standards as appropriate:
8.6.1 Soil and Soil-Rock Fills:
8.6.1.1 Field Density Test, ASTM D 1556, Density of Soil In-Place By the
Sand-Cone Method.
GI rev. 07/2015
8.6.1.2 Field Density Test, Nuclear Method, ASTM D 6938, Density of Soil and
Soil-Aggregate In-Place by Nuclear Methods (Shallow Depth).
8.6.1.3 Laboratory Compaction Test, ASTM D 1557, Moisture-Density
Relations of Soils and Soil-Aggregate Mixtures Using 10-Pound
Hammer and 18-Inch Drop.
8.6.1.4. Expansion Index Test, ASTM D 4829, Expansion Index Test.
9. PROTECTION OF WORK
9.1 During construction, the Contractor shall properly grade all excavated surfaces to provide
positive drainage and prevent ponding of water. Drainage of surface water shall be
controlled to avoid damage to adjoining properties or to finished work on the site. The
Contractor shall take remedial measures to prevent erosion of freshly graded areas until
such time as permanent drainage and erosion control features have been installed. Areas
subjected to erosion or sedimentation shall be properly prepared in accordance with the
Specifications prior to placing additional fill or structures.
9.2 After completion of grading as observed and tested by the Consultant, no further
excavation or filling shall be conducted except in conjunction with the services of the
Consultant.
10. CERTIFICATIONS AND FINAL REPORTS
10.1 Upon completion of the work, Contractor shall furnish Owner a certification by the Civil
Engineer stating that the lots and/or building pads are graded to within 0.1 foot vertically of
elevations shown on the grading plan and that all tops and toes of slopes are within 0.5 foot
horizontally of the positions shown on the grading plans. After installation of a section of
subdrain, the project Civil Engineer should survey its location and prepare an as-built plan
of the subdrain location. The project Civil Engineer should verify the proper outlet for the
subdrains and the Contractor should ensure that the drain system is free of obstructions.
10.2 The Owner is responsible for furnishing a final as-graded soil and geologic report
satisfactory to the appropriate governing or accepting agencies. The as-graded report
should be prepared and signed by a California licensed Civil Engineer experienced in
geotechnical engineering and by a California Certified Engineering Geologist, indicating
that the geotechnical aspects of the grading were performed in substantial conformance
with the Specifications or approved changes to the Specifications.
41571 Corning Place, Suite 101 ■ Murrieta, California 92562 ■ Telephone 951.304.2300 ■ www.geoconinc.com
Project No. T2754-22-06
June 20, 2022
REVISED: August 2, 2022
LC Investments 2010, LLC
d/b/a Omni La Costa Resort & Spa
4001 Maple Avenue, Suite 300
Dallas Texas 75219
Attention: Mr. Clint Gulick
Subject: INFILTRATION TESTING & PERVIOUS PAVING RECOMMENDATIONS
OMNI LA COSTA RESORT & SPA
2100 COSTA DEL MAR ROAD
CARLSBAD, CALIFORNIA
Dear Mr. Gulick:
In accordance with your authorization of our proposal IE-3013 dated May 13, 2022, Geocon West, Inc.
(Geocon) herein submits the results of our infiltration testing for the design of a proposed stormwater
basin northeast of the intersection of El Camino Real and Costa Del Mar Road near the resort entrance,
and for the design of pervious paving along the southern side of the golf course parking immediately
north of San Marcos Creek and east of El Camino Real, in the City of Carlsbad, California (Vicinity
Map, Figure 1).
The primary geologic units at the site are old alluvium and young alluvium (Kennedy et. al., 2007).
Old alluvium deposits were encountered in each boring at the location of the proposed stormwater
basin to the maximum depth explored of 20½ feet. The old alluvium consists of silty sand that can be
characterized as medium dense to dense, slightly moist to moist, and strong brown, reddish to
yellowish brown, gray, or a mottling of these colors. Young alluvium was encountered in each boring
at the location of the proposed pervious pavers. The young alluvium consists of silty sand that can be
characterized as loose, moist to saturated, and dark brown, grayish brown, or black.
GEOCON
W E S T, I N C.
GEOTECHNI CA L ■ ENVIRONMENTAL ■ MATE RI ALSO
Geocon Project No. T2754-22-06 - 2 - REVISED August 2, 2022
PERVIOUS PAVER AREA INVESTIGATION
Infiltration Test Results
Aardvark Permeameter testing in the location of the proposed pervious paver section was completed
and the test locations are shown on Figure 2, Test Location Map. A deep geotechnical boring was
excavated to 13 feet below existing ground surface (B-1) and neither static groundwater nor
impenetrable bedrock were encountered within 10 feet of the proposed infiltration area bottoms. A log
of the geotechnical boring is presented on Figure 3. Logs of the infiltration tests are presented on
Figures 5 and 6. Infiltration test result data are presented on Figures 9 and 10.
We performed two Aardvark Permeameter tests within Borings P-1 and P-2 at the locations shown on
the Test Location Map. The test borings were 8 inches in diameter and approximately 3 feet deep.
Table 1 presents the results of the saturated hydraulic conductivity and infiltration characteristics of
on-site soil. The designer of storm water devices should apply an appropriate factor of safety, where
necessary. Soil infiltration rates from in-situ tests can vary significantly from one location to another
due to the heterogeneous characteristics inherent to most soil.
TABLE 1
INFILTRATION TEST RESULTS
Parameter P-1 P-2
Test Depth (feet) 3 3
Test Hole Radius: r (in) 8 8
Field-Saturated Infiltration Rate
(inch/hour) 0.001 0.001
Factored Infiltration Rate
(inch/hour)* 0.000 0.000
Average Factored Infiltration Rate
(inch/hour) 0.000
*Using a Factor of Safety of 2.
The results of the infiltration tests indicate an average infiltration rate of 0.001 inches per hour or 0.000
inches per hour with a factor of safety of two. Based on the results of the field infiltration tests,
infiltration would be considered infeasible.
Geocon Project No. T2754-22-06 - 3 - REVISED August 2, 2022
Pervious Paver Recommendations
We assume the planned paver area will consist of an 80 millimeter paver section, overlying a leveling
sand section, overlying a crushed aggregate base section, supported on compacted subgrade.
The aggregate base and soil subgrade should be compacted to a dry density of at least 95 percent of the
laboratory maximum dry density at or slightly above optimum moisture content as determined by
ASTM D1557. Laboratory testing indicates site soils have an R-value of 10. Paver roadway sections
should be constructed in accordance with the manufacturer’s guidelines. Recommended paver roadway
sections are presented in Table 2 below. We utilized a Gravel Factor (Gf) of 1.0 in our calculations for
the aggregate base section.
TABLE 2
PAVER DESIGN SECTION
Location
Assumed
Traffic Index
(TI)
Laboratory
R-value Leveling Sand
(inches)
Prefabricated
Concrete
Paver
(inches)
Crushed
Aggregate
Base
(inches)
Golf Course
Parking Lot 5.0 10 2 ~3⅛ 9½
Where different pavement sections are to be constructed adjacent to each other, it is recommended that
consideration be given to the use of deepened base sections to maintain a uniform base thickness and
avoid stepped cuts for placement of base material.
If planters or landscaping are planned adjacent to roadways, it is recommended that the perimeter curb
or impermeable geosynthetic material be extended at least 6 inches below the bottom of the base course
to minimize the introduction of water beneath the paving.
STORM WATER BASIN AND MANAGEMENT INVESTIGATION
We understand storm water management devices are being proposed in accordance with the 2021 City
of Carlsbad Best Management Plan (BMP) Design Manual. If not properly constructed, there is a
potential for distress to improvements and properties located hydrologically down gradient or adjacent
to these devices. 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 hydrogeological study at the site. If infiltration of storm water runoff occurs,
downstream properties may be subjected to seeps, springs, slope instability, raised groundwater,
movement of foundations and slabs, or other undesirable impacts as a result of water infiltration.
Geocon Project No. T2754-22-06 - 4 - REVISED August 2, 2022
Hydrologic Soil Group
The United States Department of Agriculture (USDA), Natural Resources Conservation Services,
possesses general information regarding the existing soil conditions for areas within the United States.
The USDA website also provides the Hydrologic Soil Group. Table 3 presents the descriptions of the
hydrologic soil groups. If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first
letter is for drained areas and the second is for undrained areas. In addition, the USDA website also
provides an estimated saturated hydraulic conductivity for the existing soil.
TABLE 3
HYDROLOGIC SOIL GROUP DEFINITIONS
Soil Group Soil Group Definition
A Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission.
B Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission.
C Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission.
D
Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These
consist chiefly of clays that have a high shrink-swell potential, soils that have a high-water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission.
The location of the proposed storm water basin is underlain by old alluvium and should be classified as
Soil Group A. The information from the USDA website can be used for the Soil Group Classification
for a potential storm water management device. Table 4 below presents the information from the
USDA website for the subject property.
TABLE 4
USDA WEB SOIL SURVEY – HYDROLOGIC SOIL GROUP
Map Unit Name Map Unit
Symbol
Approximate
Percentage of
Property
Hydrologic
Soil Group
Huerhuero land complex, 2 to 9 percent slopes HuC 100.0 D
Geocon Project No. T2754-22-06 - 5 - REVISED August 2, 2022
Percolation Testing
We excavated 2 percolation tests borings (P-3 and P-4) to 11 feet and one deep geotechnical boring to
20.5 feet below existing ground surface at the locations shown on Figure 2, Test Location Map. Neither
static groundwater nor impenetrable bedrock were encountered within 10 feet of the proposed
infiltration area bottoms. A log of the geotechnical boring is presented on Figure 4. Logs of
the infiltration tests are presented on Figures 7 and 8. Infiltration test result data are presented in
Table 5 below and on Figures 11 and 12.
We performed two Aardvark Permeameter tests within Borings P-3 and P-4 at the locations shown on
the Test Location Map. The test borings were 8 inches in diameter and approximately 11 feet deep.
Table 5 presents the results of the saturated hydraulic conductivity and infiltration characteristics of
on-site soil.
TABLE 5
INFILTRATION TEST RESULTS
Test No. Test Type
Test
Depth
(inches)
Change in
Head Over
Time
(inches)
Average
Head
(inches)
Time
Interval
(minutes)
Radius of
Test Hole
(inches)
Infiltration
Rate
(inches/hour)
P-3 Sandy 108 0.7 1.6 10 4 2.4
P-4 Sandy 108 0.3 1.8 10 4 1.0
The results of the percolation tests indicate an average infiltration rate of 1.7 inches per hour or
0.57 inches per hour with a factor of safety of three. Based on the results of the field infiltration tests,
infiltration would be considered partial.
Infiltration testing results are placed into categories that include full infiltration, partial infiltration, and no
infiltration. Table 6 below presents the commonly accepted definitions of the potential infiltration categories
based on the infiltration rates. The Categorization of Infiltration Feasibility Condition, Form I-8 is included
as Figure 15.
TABLE 6
INFILTRATION TEST RESULTS
Infiltration Category Field Infiltration Rate, I
(inches/hour)
Factored Infiltration Rate*, I
(inches/hour)
Full Infiltration I > 1.0 I > 0.5
Partial Infiltration 0.10 < I < 1.0 0.05 < I < 0.5
No Infiltration (Infeasible) I < 0.10 I < 0.05
*Using a Factor of Safety of 2.
Geocon Project No. T2754-22-06 - 6 - REVISED August 2, 2022
GEOLOGIC HAZARDS AND CONSIDERATIONS
Groundwater Elevations
We did not encounter groundwater during the excavation operations on the property. The site is at an
elevation of about 27 feet above Mean Sea Level (MSL). We expect groundwater within 50 feet from
the existing grades. Therefore, infiltration could be considered feasible based on groundwater
elevations.
Soil or Groundwater Contamination
We are unaware of contaminated soil or groundwater contamination on the property. Therefore, full
and partial infiltration associated with this risk is considered feasible.
Slope Hazards
Slopes with a height of up to 15 feet borders the west, south, and east perimeters proposed BMP site.
Based on the planned location of the basin, slopes could be impacted by infiltration. Infiltration devices
should not be installed adjacent to the top of slopes unless they are lined, possess a minimum setback
distance of 50 feet or 1.5 times the slope height, or extend below the height of the slope. .
Hydrocollapse
Hydrocollapse is the tendency of unsaturated soil structure to collapse upon saturation resulting in the
overall settlement of the effected soil and overlying foundations or improvements supported thereon.
Potentially compressible surficial soil underlying the proposed improvements is typically removed and
recompacted during remedial site grading. Based on our laboratory testing, we do not expect soils
susceptible to hydrocollapse exist; therefore, infiltration is considered feasible.
Existing Utilities
No known utilities cross the site. Infiltration due to utility concerns would be feasible.
Geocon Project No. T2754-22-06 - 7 - REVISED August 2, 2022
CONCLUSIONS AND RECOMMENDATIONS
Storm Water Infiltration Conclusion
The infiltration test results from the area of the proposed basins and storm water management devices
indicate permeability between 0.10 and 1.0 inches per hour (with a Factor of Safety of 3) resulting in a
“Partial Infiltration” condition. However, the proposed location is within 50 feet of the adjacent slopes.
Therefore, infiltration would be considered infeasible and should be lined. We have provided
recommendations for liners and subdrains herein.
Storm Water Infiltration Recommendations
Liners and subdrains should be incorporated into the design and construction of the planned storm
water devices. The liners should be impermeable (e.g. High-density polyethylene, HDPE, with a
thickness of about 30 mil or equivalent Polyvinyl Chloride, PVC) to prevent water migration.
The subdrains should be perforated within the liner area, installed at the base and above the liner, be at
least 3 inches in diameter and consist of Schedule 40 PVC pipe. The subdrains outside of the liner
should consist of solid pipe. The penetration of the liners at the subdrains should be properly
waterproofed. The subdrains should be connected to a proper outlet. The devices should also be
installed in accordance with the manufacturer’s recommendations.
Storm Water Standard Worksheets
The SWS requests the geotechnical engineer complete the Categorization of Infiltration Feasibility
Condition (Worksheet C.4-1) worksheet information to help evaluate the potential for infiltration on
the property. The attached Worksheet C.4-1 presents the completed information for the submittal
process on Figure 15.
The regional storm water standards also have a worksheet (Worksheet D.5-1) that helps the project
civil engineer estimate the factor of safety based on several factors. Table 7 describes the suitability
assessment input parameters related to the geotechnical engineering aspects for the factor of safety
determination.
Geocon Project No. T2754-22-06 - 8 - REVISED August 2, 2022
TABLE 7
SUITABILITY ASSESSMENT RELATED CONSIDERATIONS FOR INFILTRATION FACILITY
SAFETY FACTORS
Consideration High
Concern – 3 Points
Medium
Concern – 2 Points
Low
Concern – 1 Point
Assessment
Methods
Use of soil survey maps
or simple texture analysis
to estimate short-term
infiltration rates. Use of
well permeameter or
borehole methods without
accompanying continuous
boring log. Relatively
sparse testing with direct
infiltration methods
Use of well permeameter or borehole
methods with accompanying
continuous boring log. Direct
measurement of infiltration area with
localized infiltration measurement
methods (e.g., Infiltrometer).
Moderate spatial resolution
Direct measurement
with localized (i.e.
small-scale)
infiltration testing
methods at relatively
high resolution or
use of extensive test
pit infiltration
measurement
methods.
Predominant Soil
Texture
Silty and clayey soils
with significant fines Loamy soils Granular to slightly
loamy soils
Site Soil
Variability
Highly variable soils
indicated from site
assessment or unknown
variability
Soil boring/test pits indicate
moderately homogenous soils
Soil boring/test pits
indicate relatively
homogenous soils
Depth to
Groundwater/
Impervious Layer
<5 feet below
facility bottom
5-15 feet below
facility bottom
>15 feet below
facility bottom
Based on our geotechnical investigation and the previous table, Table 8 presents the estimated factor
values for the evaluation of the factor of safety for the proposed basin. These tables only present the
suitability assessment safety factor (Part A) of the worksheet. The project civil engineer should
evaluate the safety factor for design (Part B) and use the combined safety factor for the design
infiltration rate.
TABLE 8
FACTOR OF SAFETY WORKSHEET DESIGN VALUES
Suitability Assessment Factor Category Assigned
Weight (w)
Factor
Value (v)
Product
(p = w x v)
Assessment Methods 0.25 3 0.75
Predominant Soil Texture 0.25 2 0.50
Site Soil Variability 0.25 2 0.50
Depth to Groundwater/ Impervious Layer 0.25 2 0.50
Suitability Assessment Safety Factor, SA = ∑p 2.25
Geocon Project No. T2754-22-06 - 9 - REVISED August 2, 2022
Should you have any 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 C. Weidman
Staff Geologist, GIT 891
Lisa A. Battiato
CEG 2316
LCW:LAB:hd
Attachments: LIMITATIONS
REFERENCES
Figure 1, Vicinity Map
Figure 2, Test Location Map
Figure 3 and 4, Logs of Geotechnical Borings
Figures 5 through 8, Logs of Percolation Borings
Figures 9 through 12, Percolation Test Report Data
Figures 13 and 14, Grain Size Distribution Test Results
Figure15, Storm Water Standard Worksheet
Geocon Project No. T2754-22-06 REVISED August 2, 2022
LIMITATIONS AND UNIFORMITY OF CONDITIONS
1. 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 presented 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.
2. 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 or corrosive materials was not part of the scope of services
provided by Geocon.
3. This report is issued with the understanding that it is the responsibility of the owner or 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.
4. The findings of this report are valid as of the date of this report. However, changes in the
conditions of a property can occur with the passage of time, whether they be 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.
Geocon Project No. T2754-22-06 REVISED August 2, 2022
LIST OF REFERENCES
1. California Department of Water Resources, Water Data Library website,
https://wdl.water.ca.gov/ ; accessed June 2022.
2. The City of San Diego, 2018, Storm Water Standards, dated October 1.
3. Kennedy, M.P., Tan, S.S., Bovard, K.R., Alvarez, R.M., Watson, M.J., and Gutierrez, C.I.,
2007, Geologic map of the Oceanside 30x60-minute quadrangle, California, California
Geological Survey, Regional Geologic Map No. 2, 1:100,000.
SOURCE: Google Earth, 2022
VICINITY MAP
OMNI LA COSTA RESORT & SPA
2100 COSTA DEL MAR ROAD
CARLSBAD, CALIFORNIA
JUNE 2022 PROJECT NO. T2754-22-06 FIG. 1LCW
PROPOSED
BMP LOCATION
SCALE: 1” = 2000’
0’ 2000’ 4000’
PERVIOUS PAVER
LOCATION
GEOCON
W E S T, I N C.
GEOTECHNICAL ENVIRONMENTAL MATERIALS
41571 CORNING PLACE# 101 , MURRIETA, CALIFORNIA 92562
PHONE 951-304-2300 FAX 951-304-2392
I I
PROJECT NO. T2754-22-06 FIG. 2
OMNI LA COSTA RESORT & SPA
2100 COSTA DEL MAR ROAD
CARLSBAD, CALIFORNIA
TEST LOCATION MAP
LCW
Source: Google Earth, 2022.
GEOCON LEGEND
Locations are approximate
B-2
……. BORING LOCATION
JUNE 2022
……. PERCOLATION TEST LOCATIONP-4
……. PROJECT EXTENTS
B-2 P-3
P-4
B-1
P-2 P-1
SCALE: 1” = 2000’
0’ 100’ 200’GEOCO
W • S T I C.
D
EB
D
GEOTECHNICAL, ENVIRONMENTAL MATERIALS
4157 1 CORNING PLACE #101, MURRIETA, CALIFORNIA 92562
PHONE 95 1-304-2300 FAX 951-304-2392
N
B-1@0-5
B-1@5
B-1@10
CL-ML YOUNG ALLUVIUM (Qya)
Silty CLAY with sand, loose, moist, dark olive brown; fine to coarse sand;
slightly porous
- Becomes wet, gray
- Becomes black
- Becomes saturated
- No standing water
Total Depth = 13'
Groundwater not encountered
Backfilled with cuttings 5/23/2022
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 3,
Log of Boring B-1, Page 1 of 1
GEOCON
(P
.
C
.
F
.
)
DATE COMPLETED
SAMPLE SYMBOLS
SAMPLE
NO.
(B
L
O
W
S
/
F
T
.
)
BORING LOGS.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
12
CME 55
... DRIVE SAMPLE (UNDISTURBED)
PE
N
E
T
R
A
T
I
O
N
MO
I
S
T
U
R
E
BY:Weidman
5/23/22
... WATER TABLE OR SEEPAGE
DEPTH
IN
FEET
0
2
4
6
8
10
12
RE
S
I
S
T
A
N
C
E
DR
Y
D
E
N
S
I
T
Y
ELEV. (MSL.)
EQUIPMENT
BORING B-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.
T2754-22-06
-fil --xz --ifil --
--:<~ --:<~
--fil --
--~ --fil --
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-
-
-
-
-
-
-
-
-
-
-
-
B-3@0-5
B-3@5
B-3@10
B-3@15
B-3@20
SM OLD ALLUVIUM (Qya)
Silty SAND, dense, slightly moist, strong brown; fine to coarse sand; few
gravel; slightly oxidized
- Becomes moist, reddish to yellowish brown
- Becomes mottled gray and yellowish brown; fine to medium sand; trace
coarse sand; no gravel; oxidation seams; 1"-2" lenses of fine to medium,
pale yellow SP
- Becomes medium dense, wet
- Becomes dense; intebedded SP/SM
Total Depth = 20.5'
Groundwater not encountered
Backfilled with cuttings 5/23/2022
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 4,
Log of Boring B-2, Page 1 of 1
GEOCON
(P
.
C
.
F
.
)
DATE COMPLETED
SAMPLE SYMBOLS
SAMPLE
NO.
(B
L
O
W
S
/
F
T
.
)
BORING LOGS.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
27
CME 55
... DRIVE SAMPLE (UNDISTURBED)
PE
N
E
T
R
A
T
I
O
N
MO
I
S
T
U
R
E
BY:Weidman
5/23/22
... WATER TABLE OR SEEPAGE
DEPTH
IN
FEET
0
2
4
6
8
10
12
14
16
18
20
RE
S
I
S
T
A
N
C
E
DR
Y
D
E
N
S
I
T
Y
ELEV. (MSL.)
EQUIPMENT
BORING B-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.
T2754-22-06
-:-1. '-l --x lj ·1
--X · i .
X: l ( l --X .-1. -l
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--:< :·l f-t·
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-
-
-
-
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-
-
-
-
-
-
-
-
-
-
-
-
P-1@3'
CL-ML TOPSOIL
3" thick, grass @ surface
YOUNG ALLUVIUM (Qya)
Silty CLAY with sand, loose, moist, dark olive brown; fine to coarse sand
Total Depth = 3'
Groundwater not encountered
Backfilled with cuttings 5/25/2022
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 5,
Log of Boring P-1, Page 1 of 1
GEOCON
(P
.
C
.
F
.
)
DATE COMPLETED
SAMPLE SYMBOLS
SAMPLE
NO.
(B
L
O
W
S
/
F
T
.
)
BORING LOGS.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
11
CME 55
... DRIVE SAMPLE (UNDISTURBED)
PE
N
E
T
R
A
T
I
O
N
MO
I
S
T
U
R
E
BY:Weidman
5/23/22
... WATER TABLE OR SEEPAGE
DEPTH
IN
FEET
0
2
RE
S
I
S
T
A
N
C
E
DR
Y
D
E
N
S
I
T
Y
ELEV. (MSL.)
EQUIPMENT
BORING P-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.
T2754-22-06
---:-1. '-l
--rt·1_
-~: l fl
I]
ii
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I -
-
P-2@3'
CL-ML TOPSOIL
3" thick, grass @ surface
YOUNG ALLUVIUM (Qya)
Silty CLAY with sand, loose, moist, dark olive brown; fine to coarse sand
Total Depth = 3'
Groundwater not encountered
Backfilled with cuttings 5/25/2022
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 6,
Log of Boring P-2, Page 1 of 1
GEOCON
(P
.
C
.
F
.
)
DATE COMPLETED
SAMPLE SYMBOLS
SAMPLE
NO.
(B
L
O
W
S
/
F
T
.
)
BORING LOGS.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
12
CME 55
... DRIVE SAMPLE (UNDISTURBED)
PE
N
E
T
R
A
T
I
O
N
MO
I
S
T
U
R
E
BY:Weidman
5/23/22
... WATER TABLE OR SEEPAGE
DEPTH
IN
FEET
0
2
RE
S
I
S
T
A
N
C
E
DR
Y
D
E
N
S
I
T
Y
ELEV. (MSL.)
EQUIPMENT
BORING P-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.
T2754-22-06
---:-1. '-l
--rt·1_
-~: l fl
I]
ii
■
_y
I -
-
P-3@5'
SM OLD ALLUVIUM (Qya)
Silty SAND, medium dense, slightly moist, strong brown; fine to coarse
sand; few gravel
- Becomes dense
- Becomes reddish to yellowish brown, moist
Total Depth = 11'
Groundwater not encountered
Backfilled with cuttings 5/25/2022
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 7,
Log of Boring P-3, Page 1 of 1
GEOCON
(P
.
C
.
F
.
)
DATE COMPLETED
SAMPLE SYMBOLS
SAMPLE
NO.
(B
L
O
W
S
/
F
T
.
)
BORING LOGS.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
27
CME 55
... DRIVE SAMPLE (UNDISTURBED)
PE
N
E
T
R
A
T
I
O
N
MO
I
S
T
U
R
E
BY:Weidman
5/23/22
... WATER TABLE OR SEEPAGE
DEPTH
IN
FEET
0
2
4
6
8
10
RE
S
I
S
T
A
N
C
E
DR
Y
D
E
N
S
I
T
Y
ELEV. (MSL.)
EQUIPMENT
BORING P-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.
T2754-22-06
-:-1. '-l --ll ·1 --:·l f-t· --.-1. -l
--ll ·1
--:·l f-t·
.-1. -l --ll ·1 --:·l f-t· --.-1. -l --ll ·1
--:·l f-t· -~ -1. -l
I]
ii
■
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-
-
-
-
-
-
-
-
-
-
P-3@5'
SM OLD ALLUVIUM (Qya)
Silty SAND, medium dense, slightly moist, strong brown; fine to coarse
sand
- Becomes dense, reddish to yellowish brown; few gravel
- Becomes dark brown; fine to medium sand; no gravel
- Becomes gray
Total Depth = 11'
Groundwater not encountered
Backfilled with cuttings 5/25/2022
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 8,
Log of Boring P-4, Page 1 of 1
GEOCON
(P
.
C
.
F
.
)
DATE COMPLETED
SAMPLE SYMBOLS
SAMPLE
NO.
(B
L
O
W
S
/
F
T
.
)
BORING LOGS.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
27
CME 55
... DRIVE SAMPLE (UNDISTURBED)
PE
N
E
T
R
A
T
I
O
N
MO
I
S
T
U
R
E
BY:Weidman
5/23/22
... WATER TABLE OR SEEPAGE
DEPTH
IN
FEET
0
2
4
6
8
10
RE
S
I
S
T
A
N
C
E
DR
Y
D
E
N
S
I
T
Y
ELEV. (MSL.)
EQUIPMENT
BORING P-4
... 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.
T2754-22-06
-:-1. '-l --ll ·1 --:·l f-t· --.-1. -l
--ll ·1
--:·l f-t·
.-1. -l --ll ·1 --:·l f-t· --.-1. -l --ll ·1
--:·l f-t· -~ -1. -l
I]
ii
■
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-
-
-
-
-
-
-
-
-
-
TEST NO.:P-1 GEOLOGIC UNIT:Qya
EXCAVATION ELEVATION (MSL, FT):27
Reading Time Elapsed
(min)
Water Weight
Consumed (lbs)
Water Volume
Consumed (in3)Q (in3/min)
1 0.00 0.000 0.00 0.00
2 5.00 0.245 6.78 1.357
3 5.00 0.150 4.15 0.831
4 5.00 0.020 0.55 0.111
5 5.00 0.010 0.28 0.055
6 5.00 0.005 0.14 0.028
7 5.00 0.005 0.14 0.028
8 5.00 0.000 0.00 0.000
9 5.00 0.005 0.14 0.028
10 5.00 0.005 0.14 0.028
11 5.00 0.005 0.14 0.028
12 5.00 0.005 0.14 0.028
13 5.00 0.005 0.14 0.028
14 5.00 0.005 0.14 0.028
TEST RESULTS
FIELD-SATURATED INFILTRATION RATE (IN/HR):
FACTORED INFILTRATION RATE (IN/HR):
0.001
0.000
STEADY FLOW RATE (IN3/MIN):0.028
TEST DATA
AARDVARK PERMEAMETER TEST RESULTS
OMNI LA COSTA
PROJECT NO.:T2754-22-06
TEST INFORMATION
BOREHOLE DIAMETER (IN):8
3.0
24
FACTOR OF SAFETY: 2.0
BOREHOLE DEPTH (FT):
TEST/BOTTOM ELEVATION (MSL, FT):
MEASURED HEAD HEIGHT (IN):
CALCULATED HEAD HEIGHT (IN):
19.0
5.6
0.0
1.0
2.0
3.0
4.0
5.0
0 5 10 15 20 25 30 35 40 45 50
Q (i
n
3/m
i
n
)
Time (min)
-r---._
GEOCO s C .
, NVIRONMENTAL, MATERIALS
41571 CORNING PLACE II IOI. MURRIE-T~ CM.IFORNIA 92.5fi'2
PHON 951-304-?300 FAX 9.!I I ..1C14-2392
TEST NO.:P-2 GEOLOGIC UNIT:Qya
EXCAVATION ELEVATION (MSL, FT):27
Reading Time Elapsed
(min)
Water Weight
Consumed (lbs)
Water Volume
Consumed (in3)Q (in3/min)
1 0.00 0.000 0.00 0.00
2 5.00 0.150 4.15 0.831
3 5.00 0.005 0.14 0.028
4 5.00 0.005 0.14 0.028
5 5.00 0.000 0.00 0.000
6 5.00 0.005 0.14 0.028
7 5.00 0.005 0.14 0.028
8 5.00 0.005 0.14 0.028
9 5.00 0.005 0.14 0.028
10 5.00 0.000 0.00 0.000
11 5.00 0.005 0.14 0.028
12 5.00 0.005 0.14 0.028
13 5.00 0.005 0.14 0.028
14 5.00 0.005 0.14 0.028
FACTOR OF SAFETY: 2.0
BOREHOLE DEPTH (FT):
TEST/BOTTOM ELEVATION (MSL, FT):
MEASURED HEAD HEIGHT (IN):
CALCULATED HEAD HEIGHT (IN):
20.0
5.6
TEST INFORMATION
BOREHOLE DIAMETER (IN):8
3.0
24
TEST RESULTS
FIELD-SATURATED INFILTRATION RATE (IN/HR):
FACTORED INFILTRATION RATE (IN/HR):
0.001
0.000
STEADY FLOW RATE (IN3/MIN):0.018
TEST DATA
AARDVARK PERMEAMETER TEST RESULTS
OMNI LA COSTA
PROJECT NO.:T2754-22-06
0.0
1.0
2.0
3.0
4.0
5.0
0 5 10 15 20 25 30 35 40 45 50
Q (i
n
3/m
i
n
)
Time (min)
-----
GEOCO
W E S T . I C.
GEOTI:CHNICAL, ENVIRONMENTAL, MATERIALS
41571 CORNING PLAC E 1101. Ml.RRIETA. CALIFORNIA '2S62
PHON 951-304-2300 F-AX PS I-304-23'2
Project Name:Omni La Costa Project No.:T2754-22-06
Test Hole No.:P-3 Date Excavated:5/23/2022
Length of Test Pipe:132.0 inches Soil Classification:SM
Height of Pipe above Ground:0.0 inches Presoak Date:5/25/2022
Depth of Test Hole:132.0 inches Perc Test Date:5/25/2022
Check for Sandy Soil Criteria Tested by:Weidman Percolation Tested by:Weidman
Trial No. Time Time Total Initial Water Final Water in Water Percolation
Interval Elapsed Level Level Level Rate
(min) Time (min) (in) (in) (in) (min/inch)
7:30 AM
7:55 AM
7:55 AM
8:20 AM
Reading Time Time Total Initial Water Final Water in Water Percolation
No. Interval Elapsed Head Head Level Rate
(min) Time (min) (in) (in) (in) (min/inch)
8:30 AM
8:40 AM
8:40 AM
8:50 AM
8:50 AM
9:00 AM
9:00 AM
9:10 AM
9:10 AM
9:20 AM
9:20 AM
9:30 AM
Infiltration Rate (in/hr):4.8
Radius of test hole (in):4 Figure - 11
Average Head (in):19.7
PERCOLATION TEST REPORT
Water level measured from BOTTOM of hole
Sandy Soil Criteria Test
1 25 25 24.0 0.0 24.0 1.0
2 25 50 24.0 0.2 23.8
1 10 10 24.0 6.6 17.4
20 24.0 11.0 13.0
1.1
Soil Criteria: Sandy
0.6
0.8
Percolation Test
3 10 30 24.0 13.7 10.3 1.0
210
9.2 1.1
4 10 40 24.0 14.6 9.4
60 24.0 15.4 8.6
1.1
5 10 50 24.0 14.8
1.2610
Project Name:Omni La Costa Project No.:T2754-22-06
Test Hole No.:P-4 Date Excavated:5/23/2022
Length of Test Pipe:132.0 inches Soil Classification:SM
Height of Pipe above Ground:0.0 inches Presoak Date:5/25/2022
Depth of Test Hole:132.0 inches Perc Test Date:5/25/2022
Check for Sandy Soil Criteria Tested by:Weidman Percolation Tested by:Weidman
Trial No. Time Time Total Initial Water Final Water in Water Percolation
Interval Elapsed Level Level Level Rate
(min) Time (min) (in) (in) (in) (min/inch)
7:31 AM
7:56 AM
7:56 AM
8:21 AM
Reading Time Time Total Initial Water Final Water in Water Percolation
No. Interval Elapsed Head Head Level Rate
(min) Time (min) (in) (in) (in) (min/inch)
8:31 AM
8:41 AM
8:41 AM
8:51 AM
8:51 AM
9:01 AM
9:01 AM
9:11 AM
9:11 AM
9:21 AM
9:21 AM
9:31 AM
Infiltration Rate (in/hr):1.8
Radius of test hole (in):4 Figure - 12
Average Head (in):22.1
610
5 10 50 24.0 19.7
2.7
3.7
60 24.0 20.3 3.7
2.7
1.7
210
4.3 2.3
4 10 40 24.0 20.3
3 10 30 24.0 18.2 5.8
20 24.0 18.7 5.3
2.1
Soil Criteria: Sandy
1.8
1.9
Percolation Test
1 10 10 24.0 18.5 5.5
2 25 50 24.0 12.0 12.0
PERCOLATION TEST REPORT
Water level measured from BOTTOM of hole
Sandy Soil Criteria Test
1 25 25 24.0 0.0 24.0 1.0
Project No.: T2754-22-06
D60 D30 D10
0.11 0.073 0.073
SAMPLE
P-1@2
CLASSIFICATION
Silty CLAY with Sand (CL-ML)s, dark olive brown
Checked by:
GRAIN SIZE DISTRIBUTION Omni La Costa Resort & Spa
2100 Costa Del Mar Road
Carlsbad, CaliforniaASTM D 6913
Jun 22 Figure 13
3" 1½" ¾"⅜" #4 #10 #20 #40 #100 #200
0
10
20
30
40
50
60
70
80
90
100
0.0010.010.1110100
PE
R
C
E
N
T
PA
S
S
S
I
N
G
BY
WE
I
G
H
T
GRAIN DIAMETER, mm
U.S. STANDARD SIEVE SIZES
GRAVEL
COARSE FINE
SAND
COARSE MEDIUM FINE
SILT AND CLAY
- -- -~ ~ ~
' \
\,
GEOCON
Project No.: T2754-22-06
D60 D30 D10
0.17 0.095 0.073
SAMPLE
P-3@11
CLASSIFICATION
Silty SAND (SM), gray
Checked by:
GRAIN SIZE DISTRIBUTION Omni La Costa Resort & Spa
2100 Costa Del Mar Road
Carlsbad, CaliforniaASTM D 6913
Jun 22 Figure 14
3" 1½" ¾"⅜" #4 #10 #20 #40 #100 #200
0
10
20
30
40
50
60
70
80
90
100
0.0010.010.1110100
PE
R
C
E
N
T
PA
S
S
S
I
N
G
BY
WE
I
G
H
T
GRAIN DIAMETER, mm
U.S. STANDARD SIEVE SIZES
GRAVEL
COARSE FINE
SAND
COARSE MEDIUM FINE
SILT AND CLAY
- --""\. ----
I
GEOCON
Appendix I: Forms and Checklists
I-27 February 2016
Categorization of Infiltration Feasibility Condition Form I-8
Part 1 - Full Infiltration Feasibility Screening Criteria
Would infiltration of the full design volume be feasible from a physical perspective without any undesirable
consequences that cannot be reasonably mitigated?
Criteria Screening Question Yes No
1
Is the estimated reliable infiltration rate below proposed facility
locations greater than 0.5 inches per hour? The response to this
Screening Question shall be based on a comprehensive evaluation of
the factors presented in Appendix C.2 and Appendix D.
X
Provide basis:
Based on our test results, and utilizing a factor of safety (FOS) of 3.0 for feasibility
determination, full infiltration is feasible as the infiltration rates are lower than 0.5 in/hr.
• P-3: 4.8 in/hr (1.60 in/hr using FOS of 3.0 feasibility determination)
• P-4: 1.8 in/hr (0.60 in/hr using FOS of 3.0 feasibility determination)
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability.
2
Can infiltration greater than 0.5 inches per hour be allowed
without increasing risk of geotechnical hazards (slope stability,
groundwater mounding, utilities, or other factors) that cannot be
mitigated to an acceptable level? The response to this Screening
Question shall be based on a comprehensive evaluation of the factors
presented in Appendix C.2.
X
Provide basis:
The proposed bmp site is less than 50 feet from slopes that border the area’s northern, western, and
southern limits. Infiltration could impact these slopes. It is our opinion that infiltration cannot be
incorporated without increasing the risk of geotechnical hazards including uncontrolled water lateral
migration, settlement, shrinking and swelling, and impacts to nearby utilities.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability.
Appendix I: Forms and Checklists
I-28 February 2016
Form I-8 Page 2 of 4
Criteria Screening Question Yes No
3
Can infiltration greater than 0.5 inches per hour be allowed
without increasing risk of groundwater contamination (shallow
water table, storm water pollutants or other factors) that cannot
be mitigated to an acceptable level? The response to this Screening
Question shall be based on a comprehensive evaluation of the factors
presented in Appendix C.3.
X
Provide basis:
We did not encounter groundwater during our investigation. We expect the groundwater elevation to be
less than 50 feet below existing site elevations. The risk of storm water infiltration adversely impacting
groundwater should be considered.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability.
4
Can infiltration greater than 0.5 inches per hour be allowed
without causing potential water balance issues such as change of
seasonality of ephemeral streams or increased discharge of
contaminated groundwater to surface waters? The response to this
Screening Question shall be based on a comprehensive evaluation of
the factors presented in Appendix C.3.
X
Provide basis:
It is our opinion that infiltration should not cause water balance issues or increased discharge of
contaminated groundwater to surface waters.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability.
Part 1
Result
*
If all answers to rows 1 - 4 are “Yes” a full infiltration design is potentially feasible. The
feasibility screening category is Full Infiltration
If any answer from row 1-4 is “No”, infiltration may be possible to some extent but
would not generally be feasible or desirable to achieve a “full infiltration” design.
Proceed to Part 2
No
*To be completed using gathered site information and best professional judgment considering the definition of MEP in
the MS4 Permit. Additional testing and/or studies may be required by the City to substantiate findings
Appendix I: Forms and Checklists
I-29 February 2016
Form I-8 Page 3 of 4
Part 2 – Partial Infiltration vs. No Infiltration Feasibility Screening Criteria
Would infiltration of water in any appreciable amount be physically feasible without any negative
consequences that cannot be reasonably mitigated?
Criteria Screening Question Yes No
5
Do soil and geologic conditions allow for infiltration in any
appreciable rate or volume? The response to this Screening
Question shall be based on a comprehensive evaluation of the factors
presented in Appendix C.2 and Appendix D.
X
Provide basis:
Based on our test results, and utilizing a factor of safety (FOS) of 3.0 for feasibility
determination, full infiltration is feasible as the infiltration rates are lower than 0.5 in/hr.
• P-3: 4.8 in/hr (1.60 in/hr using FOS of 3.0 feasibility determination)
• P-4: 1.8 in/hr (0.60 in/hr using FOS of 3.0 feasibility determination)
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates.
6
Can Infiltration in any appreciable quantity be allowed without
increasing risk of geotechnical hazards (slope stability,
groundwater mounding, utilities, or other factors) that cannot
be mitigated to an acceptable level? The response to this Screening
Question shall be based on a comprehensive evaluation of the factors
presented in Appendix C.2.
X
Provide basis:
The proposed bmp site is less than 50 feet from slopes that border the area’s northern, western, and
southern limits. Infiltration could impact these slopes. It is our opinion that infiltration cannot be
incorporated without increasing the risk of geotechnical hazards including uncontrolled water lateral
migration, settlement, shrinking and swelling, and impacts to nearby utilities.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates.
Appendix I: Forms and Checklists
I-30 February 2016
Form I-8 Page 4 of 4
Criteria Screening Question Yes No
7
Can Infiltration in any appreciable quantity be allowed without
posing significant risk for groundwater related concerns
(shallow water table, storm water pollutants or other factors)?
The response to this Screening Question shall be based on a
comprehensive evaluation of the factors presented in Appendix C.3.
X
Provide basis:
We did not encounter groundwater during our investigation. We expect the groundwater elevation to be
less than 50 feet below existing site elevations. The risk of storm water infiltration adversely impacting
groundwater should be considered.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates.
8
Can infiltration be allowed without violating downstream water
rights? The response to this Screening Question shall be based on a
comprehensive evaluation of the factors presented in Appendix C.3.
X
Provide basis:
Researching downstream water rights and evaluating water balance issues to stream flows is beyond the
scope of the geotechnical engineer. However, it is our opinion that infiltration should not impact downstream
water rights.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates.
Part 2
Result*
If all answers from row 5-8 are yes then partial infiltration design is potentially feasible.
The feasibility screening category is Partial Infiltration.
If any answer from row 5-8 is no, then infiltration of any volume is considered to be
infeasible within the drainage area. The feasibility screening category is No Infiltration.
No
*To be completed using gathered site information and best professional judgment considering the definition of MEP in
the MS4 Permit. Additional testing and/or studies may be required by the City to substantiate findings
41571 Corning Place, Suite 101 ■ Murrieta, California 92562 ■ Telephone 951.304.2300 ■ www.geoconinc.com
Project No. T2754-22-06
February 2, 2023
REVISED March 21, 2023
LC Investments 2010, LLC
d/b/a Omni La Costa Resort & Spa
4001 Maple Avenue, Suite 300
Dallas Texas 75219
Attention: Mr. Clint Gulick
Subject: INFILTRATION TEST REPORT
OMNI LA COSTA RESORT & SPA
2100 COSTA DEL MAR ROAD
CARLSBAD, CALIFORNIA
Dear Mr. Gulick:
In accordance with your authorization, Geocon West, Inc. (Geocon) herein submits the results of
additional infiltration testing required by the City of Carlsbad for the design of a proposed stormwater
infiltration structure southeast of Arenal Road and Estrella De Mar Road in the City of Carlsbad,
California (Vicinity Map, Figure 1).
The site of the proposed infiltration structure was explored on January 31, 2023, by excavating two
hand auger borings. The primary geologic units at the site are undocumented fill which overlies old
alluvial flood plain deposits. The units were encountered in each boring at the location of the proposed
stormwater structure, see Figure 2, to the maximum depth explored of 4 feet. The units consist
primarily of silty sand. The fill can be characterized as medium dense, wet, and dark brown. The old
alluvial flood plain deposits can be characterized as medium dense, wet, reddish brown with gray, and
slightly oxidized.
Aardvark Permeameter testing was completed, and the test locations are shown on Figure 2,
Test Location Map. Logs of the percolation borings are presented on Figures 3 and 4. Percolation test
report data are presented on Figures 5 and 6.
STORM WATER BASIN AND MANAGEMENT INVESTIGATION
We understand storm water management devices are being proposed in accordance with the 2021 City
of Carlsbad Best Management Plan (BMP) Design Manual. If not properly constructed, there is a
potential for distress to improvements and properties located hydrologically down gradient or adjacent
to these devices. 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 hydrogeological study at the site. If infiltration of storm water runoff occurs,
downstream properties may be subjected to seeps, springs, slope instability, raised groundwater,
movement of foundations and slabs, or other undesirable impacts as a result of water infiltration.
GEOCON
W E S T, I N C . S
RON MENTAL ■ MATERIAL GEOTECHNICAL ■ ENVI
Geocon Project No. T2754-22-06 - 2 - February 2, 2023
REVISED March 21, 2023
Hydrologic Soil Group
The United States Department of Agriculture (USDA), Natural Resources Conservation Services,
possesses general information regarding the existing soil conditions for areas within the United States.
The USDA website also provides the Hydrologic Soil Group. Table 1 presents the descriptions of the
hydrologic soil groups. If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first
letter is for drained areas and the second is for undrained areas. In addition, the USDA website also
provides an estimated saturated hydraulic conductivity for the existing soil.
TABLE 1
HYDROLOGIC SOIL GROUP DEFINITIONS
Soil Group Soil Group Definition
A Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission.
B
Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately
deep or deep, moderately well drained or well drained soils that have moderately fine texture to
moderately coarse texture. These soils have a moderate rate of water transmission.
C Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission.
D
Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high-water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission.
The location of the proposed storm water basin is underlain by old alluvial flood plain deposits and
should be classified as Soil Group C. The information from the USDA website can be used for the Soil
Group Classification for a potential storm water management device. Table 2 below presents the
information from the USDA website for the subject property.
TABLE 2
USDA WEB SOIL SURVEY – HYDROLOGIC SOIL GROUP
Map Unit Name Map Unit
Symbol
Approximate
Percentage of
Property
Hydrologic
Soil Group
Huerhuero land complex, 9 to 30 percent slopes HuE 100.0 D
Geocon Project No. T2754-22-06 - 3 - February 2, 2023
REVISED March 21, 2023
Aardvark Permeameter Testing
We performed two Aardvark Permeameter tests within Borings P-7 and P-8 at the locations shown on
the Test Location Map. Boring logs are presented on Figures 3 and 4. The test borings were 6 inches in
diameter and approximately 4 feet deep. Table 3 presents the results of the saturated hydraulic
conductivity and infiltration characteristics of on-site soil. The designer of storm water devices should
apply an appropriate factor of safety, where necessary. Soil infiltration rates from in-situ tests can vary
significantly from one location to another due to the heterogeneous characteristics inherent to most
soil.
TABLE 3
INFILTRATION TEST RESULTS
Parameter P-7 P-8
Test Depth (feet) 4 4
Test Hole Radius: r (in) 3 3
Field-Saturated Infiltration Rate
(inch/hour) 0.019 0.075
Factored Infiltration Rate
(inch/hour)* 0.010 0.037
Average Factored Infiltration Rate
(inch/hour) 0.024
*Using a Factor of Safety of 2.
The results of the infiltration tests indicate an average infiltration rate of 0.047 inches per hour or
0.024 inches per hour with a factor of safety of 2 applied. Based on the results of the field infiltration
tests, infiltration would be considered infeasible.
Infiltration testing results are placed into categories that include full infiltration, partial infiltration, and no
infiltration. Table 4 below presents the commonly accepted definitions of the potential infiltration categories
based on the infiltration rates. The Categorization of Infiltration Feasibility Condition, Form I-8 is included
as Figure 7.
TABLE 4
INFILTRATION TEST RESULTS
Infiltration Category Field Infiltration Rate, I
(inches/hour)
Factored Infiltration Rate*, I
(inches/hour)
Full Infiltration I > 1.0 I > 0.5
Partial Infiltration 0.10 < I < 1.0 0.05 < I < 0.5
No Infiltration (Infeasible) I < 0.10 I < 0.05
*Using a Factor of Safety of 2.
Geocon Project No. T2754-22-06 - 4 - February 2, 2023
REVISED March 21, 2023
GEOLOGIC HAZARDS AND CONSIDERATIONS
Groundwater Elevations
We did not encounter groundwater during the excavation operations on the property. The site is at an
elevation of about 73 feet above Mean Sea Level (MSL). We expect groundwater within 100 feet from
the existing grades. Therefore, infiltration could be considered feasible based on groundwater
elevations.
Soil or Groundwater Contamination
We are unaware of contaminated soil or groundwater contamination on the property. Therefore, full
and partial infiltration associated with this risk is considered feasible.
Slope Hazards
Slopes with a total height of up to 50 feet are east of the proposed BMP site. Infiltration devices should
not be installed adjacent to the top of slopes unless they are lined, possess a minimum setback distance
of 50 feet or 1.5 times the slope height, or extend below the height of the slope. Based on the planned
location of the infiltration structure, the slopes are 75 feet from the basin, infiltration would be feasible.
Existing Utilities
No known utilities cross the site. Infiltration due to utility concerns would be feasible.
Geocon Project No. T2754-22-06 - 5 - February 2, 2023
REVISED March 21, 2023
CONCLUSIONS AND RECOMMENDATIONS
Storm Water Infiltration Conclusion
The infiltration test results from the area of the proposed basins and storm water management devices
indicate infiltration rates between 0.010 and 0.037 inches per hour (with a Factor of Safety of 2)
resulting in a “Partial Infiltration” condition.
Storm Water Infiltration Recommendations
Liners and subdrains should be incorporated into the design and construction of the planned storm
water devices. The liners should be impermeable (e.g. High-density polyethylene, HDPE, with a
thickness of about 30 mil or equivalent Polyvinyl Chloride, PVC) to prevent water migration.
The subdrains should be perforated within the liner area, installed at the base and above the liner, be at
least 3 inches in diameter and consist of Schedule 40 PVC pipe. The subdrains outside of the liner
should consist of solid pipe. The penetration of the liners at the subdrains should be properly
waterproofed. The subdrains should be connected to a proper outlet. The devices should also be
installed in accordance with the manufacturer’s recommendations.
Storm Water Standard Worksheets
The SWS requests the geotechnical engineer complete the Categorization of Infiltration Feasibility
Condition (Worksheet C.4-1) worksheet information to help evaluate the potential for infiltration on
the property. The attached Worksheet C.4-1 presents the completed information for the submittal
process on Figure 9.
The regional storm water standards also have a worksheet (Worksheet D.5-1) that helps the project
civil engineer estimate the factor of safety based on several factors. Table 6 describes the suitability
assessment input parameters related to the geotechnical engineering aspects for the factor of safety
determination.
Geocon Project No. T2754-22-06 - 6 - February 2, 2023
REVISED March 21, 2023
TABLE 6
SUITABILITY ASSESSMENT RELATED CONSIDERATIONS FOR INFILTRATION FACILITY
SAFETY FACTORS
Consideration High
Concern – 3 Points
Medium
Concern – 2 Points
Low
Concern – 1 Point
Assessment
Methods
Use of soil survey maps
or simple texture analysis
to estimate short-term
infiltration rates. Use of
well permeameter or
borehole methods without
accompanying continuous
boring log. Relatively
sparse testing with direct
infiltration methods
Use of well permeameter or borehole
methods with accompanying
continuous boring log. Direct
measurement of infiltration area with
localized infiltration measurement
methods (e.g., Infiltrometer).
Moderate spatial resolution
Direct measurement
with localized (i.e.
small-scale)
infiltration testing
methods at relatively
high resolution or
use of extensive test
pit infiltration
measurement
methods.
Predominant Soil
Texture
Silty and clayey soils
with significant fines Loamy soils Granular to slightly
loamy soils
Site Soil
Variability
Highly variable soils
indicated from site
assessment or unknown
variability
Soil boring/test pits indicate
moderately homogenous soils
Soil boring/test pits
indicate relatively
homogenous soils
Depth to
Groundwater/
Impervious Layer
<5 feet below
facility bottom
5-15 feet below
facility bottom
>15 feet below
facility bottom
Based on our geotechnical investigation and the previous table, Table 7 presents the estimated factor
values for the evaluation of the factor of safety for the proposed basin. These tables only present the
suitability assessment safety factor (Part A) of the worksheet. The project civil engineer should
evaluate the safety factor for design (Part B) and use the combined safety factor for the design
infiltration rate.
TABLE 7
FACTOR OF SAFETY WORKSHEET DESIGN VALUES
Suitability Assessment Factor Category Assigned
Weight (w)
Factor
Value (v)
Product
(p = w x v)
Assessment Methods 0.25 2 0.50
Predominant Soil Texture 0.25 2 0.50
Site Soil Variability 0.25 2 0.50
Depth to Groundwater/ Impervious Layer 0.25 2 0.50
Suitability Assessment Safety Factor, SA = ∑p 2.00
Geocon Project No. T2754-22-06 - 7 - February 2, 2023
REVISED March 21, 2023
Should you have any 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 C. Weidman
Staff Geologist, GIT 891
Lisa A. Battiato
CEG 2316
LCW:LAB:JJV:hd
Attachments: LIMITATIONS
REFERENCES
Figure 1, Vicinity Map
Figure 2, Test Location Map
Figure 3 and 4, Logs of Percolation Borings
Figures 5 and 6, Percolation Test Report Data
Figure 7, Categorization of Infiltration Feasibility Condition, Form I-8
Distribution: Addressee (Email)
Keith Hanson, O’Day Consultants
Geocon Project No. T2754-22-06 February 2, 2023
REVISED March 21, 2023
LIMITATIONS AND UNIFORMITY OF CONDITIONS
1. 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 presented 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.
2. 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 or corrosive materials was not part of the scope of services
provided by Geocon.
3. This report is issued with the understanding that it is the responsibility of the owner or 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.
4. The findings of this report are valid as of the date of this report. However, changes in the
conditions of a property can occur with the passage of time, whether they be 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.
Geocon Project No. T2754-22-06 February 2, 2023
REVISED March 21, 2023
LIST OF REFERENCES
1. California Department of Water Resources, Water Data Library website,
https://wdl.water.ca.gov/ ; accessed February 2023.
2. The City of San Diego, 2018, Storm Water Standards, dated October 1.
3. Public Works Standards, Inc., 2021, Standard Specifications for Public Works Construction
“Greenbook,” Published by BNi Building News.
SOURCE: Google Earth, 2023
VICINITY MAP
OMNI LA COSTA RESORT & SPA
2100 COSTA DEL MAR ROAD
CARLSBAD, CALIFORNIA
MARCH 2023 PROJECT NO. T2754-22-06 FIG. 1LCW
PROPOSED
BMP LOCATION
SCALE: 1” = 2000’
0’ 2000’ 4000’
GEOCON
W E S T, I N C.
GEOTECHNICAL ENVIRONMENTAL MATERIALS
41571 CORNING PLACE# 101 , MURRIETA, CALIFORNIA 92562
PHONE 951-304-2300 FAX 951-304-2392
I I
PROJECT NO. T2754-22-06 FIG. 2
OMNI LA COSTA RESORT & SPA
2100 COSTA DEL MAR ROAD
CARLSBAD, CALIFORNIA
TEST LOCATION MAP
LCWSource: O’Day Consultants, Parking Plan, dated December 2022.
GEOCON LEGEND
Locations are approximate
MARCH 2023
……. PERCOLATION TEST LOCATIONP-8
……. PROJECT LIMITS
P-7
P-8
SCALE: 1” = 60’
0’ 60’ 120’
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GEOCO
W • S T I C.
GEOTECHNICAL, ENVIRONMENTAL MATERIALS
4157 1 CORNING PLACE #101, MURRIETA, CALIFORNIA 92562
PHONE 95 1-304-2300 FAX 951-304-2392
N
SM
SM
UNDOCUMENTED ARTIFICIAL FILL
Silty SAND, medium dense, wet, dark brown; fine to medium sand; little
coarse sand; gravel at surface
- Becomes fine to coarse sand
OLD ALLUVIAL FAN DEPOSITS
Silty SAND, medium dense, wet, reddish brown with gray; fine to coarse
sand; slightly oxidized
Total Depth = 4'
Groundwater not encountered
Backfilled with cuttings 1/31/2023
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 3,
Log of Boring P-7, Page 1 of 1
GEOCON
(P
.
C
.
F
.
)
DATE COMPLETED
SAMPLE SYMBOLS
SAMPLE
NO.
(B
L
O
W
S
/
F
T
.
)
BORING LOGS.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
75
HAND AUGER
... DRIVE SAMPLE (UNDISTURBED)
PE
N
E
T
R
A
T
I
O
N
MO
I
S
T
U
R
E
BY:Weidman
1/31/2023
... 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
BORING P-7
... 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.
T2754-22-06
\ I
I]
liiiiJ
SM
SM
UNDOCUMENTED ARTIFICIAL FILL
Silty SAND, medium dense, wet, dark brown; fine to medium sand; little
coarse sand; gravel at surface
- Becomes fine to coarse sand
- Becomes fine to medium sand
OLD ALLUVIAL FAN DEPOSITS
Silty SAND, medium dense, wet, reddish brown with gray; fine to coarse
sand; slightly oxidized
Total Depth = 4'
Groundwater not encountered
Backfilled with cuttings 1/31/2023
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 4,
Log of Boring P-8, Page 1 of 1
GEOCON
(P
.
C
.
F
.
)
DATE COMPLETED
SAMPLE SYMBOLS
SAMPLE
NO.
(B
L
O
W
S
/
F
T
.
)
BORING LOGS.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
75
HAND AUGER
... DRIVE SAMPLE (UNDISTURBED)
PE
N
E
T
R
A
T
I
O
N
MO
I
S
T
U
R
E
BY:Weidman
1/31/2023
... 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
BORING P-8
... 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.
T2754-22-06
I]
liiiiJ
TEST NO.:P-7 GEOLOGIC UNIT:afu
EXCAVATION ELEVATION (MSL, FT):73
Reading Time Elapsed
(min)
Water Weight
Consumed (lbs)
Water Volume
Consumed (in3)Q (in3/min)
1 0.00 0.000 0.00 0.00
2 5.00 3.975 110.08 22.015
3 5.00 0.065 1.80 0.360
4 5.00 0.095 2.63 0.526
5 5.00 0.045 1.25 0.249
6 5.00 0.060 1.66 0.332
7 5.00 0.050 1.38 0.277
8 5.00 0.030 0.83 0.166
9 5.00 0.030 0.83 0.166
10 5.00 0.040 1.11 0.222
11 5.00 0.035 0.97 0.194
12 5.00 0.030 0.83 0.166
13 5.00 0.025 0.69 0.13814 5.00 0.020 0.55 0.111
15 5.00 0.015 0.42 0.083
16 5.00 0.015 0.42 0.08317 5.00 0.015 0.42 0.083
18 5.00 0.015 0.42 0.083
19 5.00 0.015 0.42 0.083
FIG. 5
FACTOR OF SAFETY:2.0
BOREHOLE DEPTH (FT):
TEST/BOTTOM ELEVATION (MSL, FT):
MEASURED HEAD HEIGHT (IN):
CALCULATED HEAD HEIGHT (IN):
5.0
6.3
TEST INFORMATION
BOREHOLE DIAMETER (IN):4
4.0
69
TEST RESULTS
FIELD-SATURATED INFILTRATION RATE (IN/HR):
FACTORED INFILTRATION RATE (IN/HR):
0.019
0.010
STEADY FLOW RATE (IN3/MIN):0.083
TEST DATA
AARDVARK PERMEAMETER TEST RESULTS
OMNI LA COSTA
PROJECT NO.:T2754-22-06
0.0
1.0
2.0
3.0
4.0
5.0
0 102030405060708090
Q
(
i
n
3/m
i
n
)
Time (min)
GEOTECHNICAL, ENVIRONMENTAL, MATERIALS
41571 CORNING PLACE #101, MURRIETA, CALIFORNIA 92562
PHONE 951-304-2300 www.geoconinc.com
GEOCON
W E S T , I N C .
TEST NO.:P-8 GEOLOGIC UNIT:afu
EXCAVATION ELEVATION (MSL, FT):73
Reading Time Elapsed
(min)
Water Weight
Consumed (lbs)
Water Volume
Consumed (in3)Q (in3/min)
1 0.00 0.000 0.00 0.00
2 5.00 3.935 108.97 21.794
3 5.00 2.765 76.57 15.314
4 5.00 1.560 43.20 8.640
5 5.00 1.355 37.52 7.505
6 5.00 1.145 31.71 6.342
7 5.00 0.805 22.29 4.458
8 5.00 0.500 13.85 2.769
9 5.00 0.275 7.62 1.523
10 5.00 0.265 7.34 1.468
11 5.00 0.210 5.82 1.163
12 5.00 0.150 4.15 0.831
13 5.00 0.115 3.18 0.63714 5.00 0.095 2.63 0.526
15 5.00 0.085 2.35 0.471
16 5.00 0.075 2.08 0.41517 5.00 0.070 1.94 0.388
18 5.00 0.060 1.66 0.332
19 5.00 0.060 1.66 0.332
20 5.00 0.060 1.66 0.332
FIG. 6
FACTOR OF SAFETY:2.0
BOREHOLE DEPTH (FT):
TEST/BOTTOM ELEVATION (MSL, FT):
MEASURED HEAD HEIGHT (IN):
CALCULATED HEAD HEIGHT (IN):
6.0
6.3
TEST INFORMATION
BOREHOLE DIAMETER (IN):4
4.0
69
TEST RESULTS
FIELD-SATURATED INFILTRATION RATE (IN/HR):
FACTORED INFILTRATION RATE (IN/HR):
0.075
0.037
STEADY FLOW RATE (IN3/MIN):0.378
TEST DATA
AARDVARK PERMEAMETER TEST RESULTS
OMNI LA COSTA
PROJECT NO.:T2754-22-06
0.02.04.06.08.010.012.014.016.018.020.0
0 102030405060708090
Q
(
i
n
3/m
i
n
)
Time (min)
GEOTECHNICAL, ENVIRONMENTAL, MATERIALS
41571 CORNING PLACE #101, MURRIETA, CALIFORNIA 92562PHONE 951-304-2300 www.geoconinc.com
'-'-
' '-'-
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GEOCON
W E S T , I N C .
Appendix I: Forms and Checklists
I-27 February 2016
Categorization of Infiltration Feasibility Condition Form I-8
Part 1 - Full Infiltration Feasibility Screening Criteria
Would infiltration of the full design volume be feasible from a physical perspective without any undesirable
consequences that cannot be reasonably mitigated?
Criteria Screening Question Yes No
1
Is the estimated reliable infiltration rate below proposed facility
locations greater than 0.5 inches per hour? The response to this
Screening Question shall be based on a comprehensive evaluation of
the factors presented in Appendix C.2 and Appendix D.
X
Provide basis:
Based on our test results, and utilizing a factor of safety (FOS) of 2.0 for feasibility
determination, full infiltration is not feasible as the infiltration rates are lower than 0.5 in/hr.
• P-7: 0.010 in/hr using FOS of 2.0 feasibility determination
• P-8: 0.037 in/hr using FOS of 2.0 feasibility determination
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability.
2
Can infiltration greater than 0.5 inches per hour be allowed
without increasing risk of geotechnical hazards (slope stability,
groundwater mounding, utilities, or other factors) that cannot be
mitigated to an acceptable level? The response to this Screening
Question shall be based on a comprehensive evaluation of the factors
presented in Appendix C.2.
X
Provide basis:
The proposed bmp site is 75 feet from slopes that border the area’s eastern limits. It is our opinion that
infiltration can be incorporated without increasing the risk of geotechnical hazards including uncontrolled
water lateral migration, settlement, shrinking and swelling, and impacts to nearby utilities.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability.
Appendix I: Forms and Checklists
I-28 February 2016
Form I-8 Page 2 of 4
Criteria Screening Question Yes No
3
Can infiltration greater than 0.5 inches per hour be allowed
without increasing risk of groundwater contamination (shallow
water table, storm water pollutants or other factors) that cannot
be mitigated to an acceptable level? The response to this Screening
Question shall be based on a comprehensive evaluation of the factors
presented in Appendix C.3.
X
Provide basis:
We did not encounter groundwater during our investigation. We expect the groundwater elevation to be
less than 100 feet below existing site elevations.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability.
4
Can infiltration greater than 0.5 inches per hour be allowed
without causing potential water balance issues such as change of
seasonality of ephemeral streams or increased discharge of
contaminated groundwater to surface waters? The response to this
Screening Question shall be based on a comprehensive evaluation of
the factors presented in Appendix C.3.
X
Provide basis:
It is our opinion that infiltration should not cause water balance issues or increased discharge of
contaminated groundwater to surface waters.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability.
Part 1
Result
*
If all answers to rows 1 - 4 are “Yes” a full infiltration design is potentially feasible. The
feasibility screening category is Full Infiltration
If any answer from row 1-4 is “No”, infiltration may be possible to some extent but
would not generally be feasible or desirable to achieve a “full infiltration” design.
Proceed to Part 2
No
*To be completed using gathered site information and best professional judgment considering the definition of MEP in
the MS4 Permit. Additional testing and/or studies may be required by the City to substantiate findings
Appendix I: Forms and Checklists
I-29 February 2016
Form I-8 Page 3 of 4
Part 2 – Partial Infiltration vs. No Infiltration Feasibility Screening Criteria
Would infiltration of water in any appreciable amount be physically feasible without any negative
consequences that cannot be reasonably mitigated?
Criteria Screening Question Yes No
5
Do soil and geologic conditions allow for infiltration in any
appreciable rate or volume? The response to this Screening
Question shall be based on a comprehensive evaluation of the factors
presented in Appendix C.2 and Appendix D.
X
Provide basis:
Based on our test results, and utilizing a factor of safety (FOS) of 2.0 for feasibility
determination, full infiltration is not feasible as the infiltration rates are lower than 0.5 in/hr.
• P-7: 0.010 in/hr using FOS of 2.0 feasibility determination
• P-8: 0.037 in/hr using FOS of 2.0 feasibility determination
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates.
6
Can Infiltration in any appreciable quantity be allowed without
increasing risk of geotechnical hazards (slope stability,
groundwater mounding, utilities, or other factors) that cannot
be mitigated to an acceptable level? The response to this Screening
Question shall be based on a comprehensive evaluation of the factors
presented in Appendix C.2.
X
Provide basis:
The proposed bmp site is 75 feet from slopes that border the area’s eastern limits. It is our opinion that
infiltration cannot be incorporated without increasing the risk of geotechnical hazards including
uncontrolled water lateral migration, settlement, shrinking and swelling, and impacts to nearby utilities.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates.
Appendix I: Forms and Checklists
I-30 February 2016
Form I-8 Page 4 of 4
Criteria Screening Question Yes No
7
Can Infiltration in any appreciable quantity be allowed without
posing significant risk for groundwater related concerns
(shallow water table, storm water pollutants or other factors)?
The response to this Screening Question shall be based on a
comprehensive evaluation of the factors presented in Appendix C.3.
X
Provide basis:
We did not encounter groundwater during our investigation. We expect the groundwater elevation to be
less than 100 feet below existing site elevations.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates.
8
Can infiltration be allowed without violating downstream water
rights? The response to this Screening Question shall be based on a
comprehensive evaluation of the factors presented in Appendix C.3.
X
Provide basis:
Researching downstream water rights and evaluating water balance issues to stream flows is beyond the
scope of the geotechnical engineer. However, it is our opinion that infiltration should not impact downstream
water rights.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates.
Part 2
Result*
If all answers from row 5-8 are yes then partial infiltration design is potentially feasible.
The feasibility screening category is Partial Infiltration.
If any answer from row 5-8 is no, then infiltration of any volume is considered to be
infeasible within the drainage area. The feasibility screening category is No Infiltration.
No
*To be completed using gathered site information and best professional judgment considering the definition of MEP in
the MS4 Permit. Additional testing and/or studies may be required by the City to substantiate findings
41571 Corning Place, Suite 101 ■ Murrieta, California 92562 ■ Telephone 951.304.2300 ■ www.geoconinc.com
Project No. T2754-22-04a
July 20, 2023
LC Investments 2010, LLC
d/b/a Omni La Costa Resort & Spa
4001 Maple Avenue, Suite 300
Dallas, Texas 75219
Attention: Mr. Clint Gulick
Subject: GEOTECHNICAL RESPONSE
UPDATED THIRD-PARTY GEOTECHNICAL REVIEW
OMNI LA COSTA GOLF COURSE
2100 COSTA DEL MAR ROAD
CARLSBAD, CALIFORNIA
Dear Mr. Gulick:
This response letter has been prepared to provide geotechnical responses to Third-Party Geotechnical
Review by Ninyo & Moore dated June 30, 2023 with respect to Omni Resort Golf Course renovations
as depicted on Grading Plans prepared by O’Day Consultants dated January 2023. This letter provides
an item-by-item response to the review comments. The review comments are attached for ease of
reference.
Comment 1: The geotechnical consultant should review the project grading and foundation plans and
provide any additional geotechnical recommendations, as appropriate, and indicate if the plans have
been prepared in accordance with the geotechnical recommendations provided in the referenced
geotechnical reports (Geocon 2021, 2022a, 2022b, 2022b [sic], and 2023).
Response 1: The proposed improvements consist of landscape improvements, cart path replacements,
construction of parking lots, golf cart bridge replacements, and BMP structures. Geocon has performed
a geotechnical review of the project grading plans prepared by O’Day Consultants as detailed in the
Response to Review Sheet by Geocon dated November 22, 2022. The structural plan review was
performed as discussed in Geocon’s Plan Review Letter dated February 17, 2023. Both are attached to
this response for ease of reference. No additional geotechnical recommendations are warranted based
on planned improvements.
Comment 2: Per the City of Carlsbad (1993) Guidelines, the geotechnical consultant should provide a
geologic map.
Response 2: Geocon provided the geologic map with our grading plan review in the November 22,
2022 response to comments, attached herein for ease of reference.
GEOCON
W E S T, I N C . S
RON MENTAL ■ MATERIAL GEOTECHNICAL ■ ENVI
Geocon Project No. T2754-22-04a - 2 - July 20, 2023
Comment 3: The referenced geotechnical report (Geocon 2021) utilizes standards provided by the
2016 and 2019 California Building Code (CBC). As the standards of the 2022 CBC are the currently
accepted practices, the Geotechnical Consultant should update the report and applicable sections
utilizing those standards.
Response 3: The following information is an update utilizing 2022 California Building code and 2021
Caltrans Corrosion Guidelines. These sections do not include recommendations for slab on grade,
foundations or retaining walls as these improvements are not proposed for this project.
Expansive Soils
Based on laboratory testing of select soil samples, site soils are expected to be “expansive” in
accordance with Section 1803.5.3 of the 2022 CBC. Expansion testing of a cart path subgrade
soil sample yielded test results of 100. Therefore, site soils are expected to have “medium” to
“high” expansion potential in accordance with ASTM D4829 (Expansion Index [EI] of 51 to
130). Table 1 presents soil classifications based on the Expansion Index.
TABLE 1
SOIL CLASSIFICATION BASED ON EXPANSION INDEX
Expansion Index (EI) Expansion
Classification 2022 CBC Expansion Classification
0 – 20 Very Low Non-Expansive
21 – 50 Low
Expansive
51 – 90 Medium
91 – 130 High
Greater Than 130 Very High
Additional testing for expansion potential should be performed during grading to verify that highly
expansive soils are not present within areas where flatwork improvements are proposed.
Mitigation measures such as lime treatment of subgrade soils, placement of aggregate base
between subgrade and the PCC improvements, moisture conditioning to 4 percent above optimum
moisture, the addition of 3 inch minus rock into the upper 1 ½ feet of subgrade, and compaction of
subgrade to no more than 90 percent of dry density may be considered to mitigate expansive
subgrade soil.
The recommendations presented herein are intended to reduce the potential for cracking of
exterior slabs as a result of the impacts of expansive soils. Even with the incorporation of the
Geocon Project No. T2754-22-04a - 3 - July 20, 2023
recommendations presented herein, slab cracking and/or movement as a result of expansive soils
should be expected over time.
Corrosive Soils
Laboratory tests were performed on representative samples of the on-site soil to measure the
percentage of water-soluble sulfate content. Results indicate that the site soils possess an S2 with
values of 0.10 to 1.39 percent soluble sulfate as defined by 2022 CBC Section 1904 and ACI 318
Table 19.3.1.1. The table below presents a summary of concrete requirements set forth by 2022
CBC Section 1904 and ACI 318. The presence of water-soluble sulfates is not a visually
discernible characteristic; therefore, other soil samples from the site could yield different
concentrations. Additionally, over time landscaping activities (i.e., addition of fertilizers and
other soil nutrients) may affect the concentration.
TABLE 2
REQUIREMENTS FOR CONCRETE
EXPOSED TO SULFATE-CONTAINING SOLUTIONS
Exposure
Class
Water-Soluble Sulfate
(SO4) Percent
by Weight
Cement
Type (ASTM C150)
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
Option 1 V+Pozzolan
or Slag 0.45 4,500
Option 2 V 0.40 5,000
Laboratory test results indicate site soils at the site have an electrical resistivity of 427 ohm-cm,
and have a pH of 8.0. As shown in Table 3, would be classified as “corrosive” to buried
improvements based on the laboratory test results, in accordance with the Caltrans Corrosion
Guidelines (Caltrans, 2021). Due to the corrosive potential of the soils, it is recommended that
PVC, ABS or other approved plastic piping be utilized in lieu of cast-iron when in direct contact
with the site soils.
Geocon Project No. T2754-22-04a - 4 - July 20, 2023
TABLE 3
CALTRANS CORROSION GUIDELINES
Corrosion
Exposure
Resistivity
(ohm-cm) Chloride (ppm) Sulfate (ppm) pH
Corrosive <1,500 500 or greater 1,500 or greater 5.5 or less
Geocon West, Inc. does not practice in the field of corrosion engineering and mitigation.
If corrosion sensitive improvements are planned, it is recommended that a corrosion engineer be
retained to evaluate corrosion test results and incorporate the necessary precautions to avoid
premature corrosion of buried metal pipes and concrete structures in direct contact with the soils.
Seismic Design Criteria
The following table summarizes the site-specific design criteria obtained from the 2022
California Building Code (CBC; Based on the 2021 International Building Code [IBC] and
ASCE 7-16), Chapter 16 Structural Design, Section 1613 Earthquake Loads. The data was
calculated using the online application U.S. Seismic Design Maps, provided by the Structural
Engineers Association of California (SEAOC). The short spectral response uses a period of 0.2
second. We evaluated the Site Class based on the discussion in Section 1613.2.2 of the 2022
CBC and Table 20.3-1 of ASCE 7-16. The values presented below are for the risk-targeted
maximum considered earthquake (MCER).
TABLE 4
2022 CBC SEISMIC DESIGN PARAMETERS
Parameter Value 2022 CBC Reference
Site Class D Section 1613.2.2
MCER Ground Motion Spectral Response
Acceleration – Class B (short), SS 1.022g Figure 1613.2.1(1)
MCER Ground Motion Spectral Response
Acceleration – Class B (1 sec), S1 0.370g Figure 1613.2.1(3)
Site Coefficient, FA 1.091 Table 1613.2.3(1)
Site Coefficient, FV 1.930* Table 1613.2.3(2)
Site Class Modified MCER Spectral Response
Acceleration (short), SMS 1.115g Section 1613.2.3 (Eqn 16-20)
Site Class Modified MCER Spectral Response
Acceleration – (1 sec), SM1 0.714g* Section 1613.2.3 (Eqn 16-21)
Geocon Project No. T2754-22-04a - 5 - July 20, 2023
5% Damped Design
Spectral Response Acceleration (short), SDS 0.743g Section 1613.2.4 (Eqn 16-22)
5% Damped Design
Spectral Response Acceleration (1 sec), SD1 0.476g* Section 1613.2.4 (Eqn 16-23)
*Per Supplement 3 of ASCE 7-16, a ground motion hazard analysis (GMHA) shall be performed for projects on Site
Class “D” sites with 1-second spectral acceleration (S1) greater than or equal to 0.2g, which is true for this site.
However, Supplement 3 of ASCE 7-16 provides an exception stating that that the GMHA may be waived provided
that the parameter SM1 is increased by 50% for all applications of SM1. The values for parameters SM1 and SD1
presented above have not been increased in accordance with Supplement 3 of ASCE 7-16.
The table below 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 5
ASCE 7-16 PEAK GROUND ACCELERATION
Parameter Value ASCE 7-16 Reference
Mapped MCEG Peak Ground Acceleration,
PGA 0.449g Figure 22-9
Site Coefficient, FPGA 1.151 Table 11.8-1
Site Class Modified MCEG Peak Ground
Acceleration, PGAM 0.517g Section 11.8.3 (Eqn 11.8-1)
Deaggregation of the MCE peak ground acceleration was performed using the USGS online
Unified Hazard Tool, 2014 Conterminous U.S. Dynamic edition (v4.2.0). The result of the
deaggregation analysis indicates that the predominant earthquake contributing to the MCE peak
ground acceleration is characterized as a 6.89 magnitude event (modal) occurring at a
hypocentral distance of 10.58 kilometers from the site.
Deaggregation was also performed for the Design Earthquake (DE) peak ground acceleration,
corresponding to two-thirds of the MCE peak ground acceleration. The result of the analysis
indicates that the predominant earthquake contributing to the DE peak ground acceleration is
characterized as a 6.89 magnitude event (modal) occurring at a hypocentral distance of 10.75
kilometers from the site.
Comment 4: The referenced geotechnical report (Geocon, 2021) utilizes standards provided by the
[sic] Caltrans for the 2015 Standard Specifications, 2017 Highway design manual, and the 2018
Corrosion Guidelines. There are more recent versions of these standards, and the consultant should
review and update their report as appropriate.
Response 4: Please see our response to Comment No. 3, above.
Geocon Project No. T2754-22-04a - 6 - July 20, 2023
Comment 5: The referenced geotechnical reports (Geocon 2021, 2022a, 2022b, 2022b [sic], & 2023)
reference the 2018 City of San Diego BMP Design Manual and the 2021 City of Carlsbad BMP Design
Manual. The geotechnical consultant should review the recent version of the City of Carlsbad BMP
Design Manual and update their report and infiltration letter/forms as appropriate.
Response 5: We have compiled a Storm Water Management Investigation report in accordance with
the 2023 Carlsbad BMP Design Manual and have attached it herein.
Comment 6: The referenced geotechnical letter (Geocon, 2023) indicates a factored [sic] infiltration
rates of 0.010 and 0.037 inches per hour (with a Factor of Safety of 2). Additionally, Table 4 of the
referenced geotechnical letter (Geocon, 2023) indicates these rates coincide with a “No Infiltration”
condition However[sic], Page 5 under “Conclusions and Recommendations” states that the site is
considered a “Partial Infiltration” condition. The geotechnical consultant should review and update
their conditions as appropriate.
Response 6: Please see the attached Storm Water Management Investigation report.
Comment 7: The geotechnical consultant should provide a statement regarding the impact of the
proposed grading and construction on adjacent properties and improvements.
Response 7: Please see the response to Comment No. 2 in Geocon’s November 21, 2022, Response to
Review Comments.
Comment 8: The geotechnical consultant should provide recommendations for the inclinations of
temporary slopes.
Response 8:
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 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 geotechnical conditions expected during construction vary from dry silty sands to
saturated silts and clays. The soils should be considered Type C soils but should be
evaluated by the contractor’s competent person as the excavated slopes are exposed.
Saturated soils are likely in the golf course and driving range areas.
Excavations of up to approximately 10 feet in vertical height are expected during construction
of the proposed storm drain improvements. The contractor’s competent person should
Geocon Project No. T2754-22-04a - 7 - July 20, 2023
evaluate the necessity for lay back of vertical cut areas. Unshored vertical excavations of up
to 5 feet may be attempted where loose soils or caving sands are not present, and where not
surcharged by existing improvements or vehicle/construction equipment loads; however, the
contractor should be prepared for caving and sloughing in open excavations.
To protect existing improvements, trench shoring may be implemented. The excavation may be
conducted adjacent to existing improvements but should not extend below the surcharge area of
the existing improvement until the shoring is installed. The surcharge area may be defined by a
1:1 projection down and away from the bottom of an existing improvement.
Once shoring is installed, the excavation can be completed and the utilities can be installed. See
illustration below.
Vertical excavations greater than 5 feet will require sloping or shoring measures in order to
provide a stable excavation. We expect that shoring will be needed when in proximity to
existing roadway, utility, structural improvements, or where jack-and-bore pits are planned.
We expect that shoring, such as conventionally braced shields or cross-braced hydraulic shoring
will be utilized where shoring is needed. The selection of the shoring system is the
responsibility of the contractor. Additional recommendations for shoring pile design can be
provided under separate cover, if needed.
The stability of the excavations is dependent on the design and construction of the shoring
system and site conditions. Therefore, Geocon cannot be responsible for site safety and the
stability of the proposed excavations.
Stabilze
Utility
Trench
Bottom
Saw-cut
&
Excavate //
----,--. -----,-,_. -c_ I J
Place
Bedding Sand
&
Install Utility
Place
Hydraulic
Shoring
l
Place Shading Sand,
Place and Compact
Engineered Fill,
& Remove Shoring
Geocon Project No. T2754-22-04a - 8 - July 20, 2023
It is difficult to accurately predict the amount of deflection of a shored embankment.
Some deflection will occur. We recommend that the deflection be minimized to prevent
damage to existing structures and adjacent improvements. Where public right-of-ways are
present or adjacent offsite structures do not surcharge the shoring excavation, the shoring
deflection should be limited to less than 1 inch at the top of the shored embankment.
The allowable deflection is dependent on many factors, such as the presence of structures and
utilities near the top of the embankment and should be assessed by the contractor’s competent
person.
Comment 9: The referenced geotechnical report (Geocon, 2021) recommends that medium expansive
material can be placed within 4 feet of the proposed foundations, slab-on-grade, flatwork, or paving
improvements. The geotechnical consultant should outline mitigation methods for use of medium
expansive materials.
Response 9: Mitigation of the effects of expansive soils are provided in the referenced report:
• Moisture conditioning the fill soil to above optimum moisture;
• Foundation embedment 18 inches below lowest adjacent grade;
• Steel reinforcing bars within slabs-on-grade and concrete flatwork
• Pavement perimeter curb embedment below the level of the aggregate base materials.
.
Geocon Project No. T2754-22-04a - 9 - July 20, 2023
If you have any questions regarding this letter, or if we may be of further service, please contact the
undersigned at your convenience.
Very truly yours,
GEOCON WEST, INC.
Lisa A. Battiato
CEG 2316
LAB:ATS:JJV:hd
Andrew T. Shoashekan
PE 93940
Attachments: References
Updated Third-Party Geotechnical Review, Ninyo & Moore, dated June 30, 2023
Geotechnical Response, Geocon dated November 21, 2022
Structural Plan Review, Geocon dated February 17, 2023
Storm Water Management Investigation, Geocon, July 20, 2023
Distribution: (pdf) Addressee
(pdf) Mr. Keith Hansen, O’Day Consultants
Geocon Project No. T2754-22-04a July 20, 2023
REFERENCES
1. American Concrete Institute (ACI), 2019, Building Code Requirements for Structural
Concrete, ACI 318-19, Report by ACI Committee 318.
2. ASCE 7-16, 2022, Minimum Design Loads for Buildings and Other Structures.
3. California Building Standards Commission, 2022, California Building Code (CBC),
California Code of Regulations Title 24, Part 2.
4. California Department of Transportation (Caltrans), 2021, Division of Engineering
Services, Materials Engineering and Testing Services, Corrosion Guidelines, Version 3.2,
dated March.
5. City of Carlsbad, 2023, BMP Design Manual dated January 11.
5710 Ruffin Road | San Diego, California 92123 | p. 858.576.1000 | www.ninyoandmoore.com
June 30, 2023
Project No. 109343018
Ms. Jessica Nishiura Hunsaker & Associates
9707 Waples Street San Diego, California 92121
Subject: Updated Third-Party Geotechnical Review
Omni Resort Golf Course 2100 Costa Del Mar Road Carlsbad, California
Dear Ms. Nishiura:
At your request, we have prepared this updated letter providing our review comments to the
referenced geotechnical reports prepared by Geocon West, Inc. (Geocon) dated April 15, 2021,
June 20, 2022, August 2, 2022, September 26, 2022, and March 23, 2023. Our comments regarding
the geotechnical report include the following:
Comment 1: The geotechnical consultant should review the project grading and foundation plans and provide any additional geotechnical recommendations, as appropriate, and indicate if the plans
have been prepared in accordance with the geotechnical recommendations provided in the referenced geotechnical reports (Geocon, 2021, 2022a, 2022b, 2022b, & 2023).
Comment 2: Per the City of Carlsbad (1993) guidelines, the geotechnical consultant should provide
a geologic map.
Comment 3: The referenced geotechnical report (Geocon, 2021) utilizes the standards provided by the 2016 and 2019 California Building Code (CBC). As the standards of the 2022 CBC are the
currently accepted practices, the Geotechnical Consultant should update the report and applicable sections utilizing those standards.
Comment 4: The referenced geotechnical report (Geocon, 2021) utilizes the standards provided by the Caltrans for the 2015 Standard Specifications, 2017 Highway Design Manual, and the 2018 Corrosion Guidelines. There are more recent versions of these standards and the consultant should review and update their report as appropriate.
Comment 5: The referenced geotechnical reports (Geocon, 2021, 2022a, 2022b, 2022b, & 2023) reference the 2018 City of San Diego BMP Design Manual and the 2021 City of Carlsbad BMP Design Manual. The geotechnical consultant should review the recent version of the City of Carlsbad BMP Design Manual and update their report and infiltration letter/forms as appropriate.
JVin90&,v\OOl"'e
Geotechnical & Environmental Sciences Consultants
Ninyo & Moore | 2100 Costa Del Mar Road, Carlsbad, California | 109343018 | June 30, 2023 2
Comment 6: The referenced geotechnical letter (Geocon, 2023) indicates a factored infiltration rates
of 0.010 and 0.037 inches per hour (with a Factor of Safety of 2). Additionally, Table 4 of the referenced geotechnical letter (Geocon, 2023) indicates that these rates coincide with a “No Infiltration” condition However, Page 5 under “Conclusions and Recommendations” states that the
site is considered a “Partial Infiltration” condition. The geotechnical consultant should review and update their conclusions as appropriate.
Comment 7: The geotechnical consultant should provide a statement regarding the impact of the
proposed grading and construction on adjacent properties and improvements.
Comment 8: The geotechnical consultant should provide recommendations for inclinations of temporary slopes.
Comment 9: The referenced geotechnical report (Geocon, 2021) recommends that medium expansive material can be placed within 4 feet of the proposed foundations, slab-on-grade, flatwork, or paving improvements. The geotechnical consultant should outline mitigation methods for use of medium expansive materials.
We appreciate the opportunity to be of service.
Respectfully submitted, NINYO & MOORE
Christine M. Kuhns, PE Project Engineer Jeffrey T. Kent, PE, GE Principal Engineer
CMK/JTK/mp
Attachment: References
d '--------------
Ninyo & Moore | 2100 Costa Del Mar Road, Carlsbad, California | 109343018 | June 30, 2023 1
REFERENCES
California Building Standards Commission, 2022, California Building Code: California Code of Regulations, Title 24, Part 2, Volumes 1 and 2.
California Department of Transportation (Caltrans), 2021, Corrosion Guidelines (Version 3.2), Division of Engineering and Testing Services, Corrosion Technology Branch: dated May.
City of Carlsbad, 1993, Technical Guidelines For Geotechnical Reports: dated January.
City of Carlsbad, 2023, BMP Design Manual: dated January 11.
City of Carlsbad., 2023, Grading Plans for Omni Resort Golf Course, Carlsbad, California 92009: dated April.
Geocon West, Inc. (Geocon), 2021, Limited Geotechnical Evaluation, Champions Course Renovations, Omni La Costa Resort & Spa, 2100 Costa Del Mar Road, Carlsbad, California
92009, Project No. T2754-22-04: dated April 15.
Geocon West, Inc. (Geocon), 2022a, Infiltration Testing and Pervious Paving Recommendations, Omni La Costa Resort & Spa, 2100 Costa Del Mar Road, Carlsbad, California 92009, Project
No. T2754-22-06: dated June 20.
Geocon West, Inc. (Geocon), 2022b, Infiltration Testing and Pervious Paving Recommendations, Omni La Costa Resort & Spa, 2100 Costa Del Mar Road, Carlsbad, California 92009, Project
No. T2754-22-06: revised date of August 2.
Geocon West, Inc. (Geocon), 2022c, Infiltration Testing and Pavement Recommendations, Omni La Costa Resort & Spa, 2100 Costa Del Mar Road, Carlsbad, California 92009, Project No. T2754-22-06: dated September 26.
Geocon West, Inc. (Geocon), 2023, Infiltration Test Report, Omni La Costa Resort & Spa, 2100 Costa Del Mar Road, Carlsbad, California 92009, Project No. T2754-22-06: dated February 2, Revised March 21.
d -------------------------
Project No. T2754-22-04
October 10, 2022
REVISED November 21, 2022
LC Investments 2010, LLC
d/b/a Omni La Costa Resort & Spa
4001 Maple Avenue, Suite 300
Dallas, Texas 75219
Attention: Mr. Clint Gulick
Subject: GEOTECHNICAL RESPONSE
GEOTECHNICAL REPORT REVIEW LETTER DATED SEPTEMBER 28, 2022
OMNI LA COSTA GOLF COURSE
GRADING PERMIT NO. GR2022-0038, PROJECT ID: SUP2022-0001
CARLSBAD, CALIFORNIA
References: 1. Geotechnical Report Review, Omni La Costa Golf Course (1st review) dated
September 28, 2022, prepared by the City of Carlsbad.
2. Rough Grading Plan for Omni Resort Golf Course, Sheets 1 through 22, dated
September 1, 2022, prepared by O’Day Consultants
3. Limited Geotechnical Investigation, Champions Course Renovations, Omni La
Costa Resort & Spa, 2100 Costa Del Mar Road, Carlsbad, California, Project T2754-
22-04, dated April 15, 2021, prepared by Geocon West, Inc.
Dear Mr. Gulick:
This response letter has been prepared to provide geotechnical responses to report review questions
presented in the City of Carlsbad Geotechnical Report Review letter dated September 28, 2022
(Reference1) with respect to the Limited Geotechnical Investigation report prepared by Geocon West,
Inc. (Geocon) dated April 15, 2022 (Reference 3). This provides an item-by-item response to the
review comments. Reference 1 is attached herein for ease of reference.
This response has been revised to correct a typo in Geocon’s response to Comment 9.
Comment 1: Please review the most current grading plan for the project and provide any additional
geotechnical recommendations or modifications to the geotechnical report, as necessary.
Response 1: Geocon has reviewed the grading plans (Reference 2) which depict the proposed
improvements to include: realignment of cart paths, filling of the pond in the northern portion of the
Course; cuts and fills of 5 feet or less to level some areas of the site and to raise other areas; and
construction of three cart path and foot bridges that will span 25 feet or less. Geocon has considered the
final proposed improvements depicted on reference 2 with respect to the Limited Geotechnical
GEOCON
W E S T, I N C.
GEOTECHNICA L ■ ENVIRONMENTAL ■ MATERIALS °'
41571 Corning Ploce, Suite l 01 ■ Murrieto, Colilornio 92562-7065 ■ Telephone 951.304.2300 ■ Fox 951 .304.2392
Geocon Project No. T2754-22-04 - 2 - REVISED November 21, 2022
Investigation report (Reference 3) and the expected improvements are generally similar to those
proposed at the time of Reference 3 in 2021 with the exception that no retaining walls are proposed on
the plans. Reference 3 remains applicable to the project unless superseded herein.
Comment 2: Please provide a statement addressing the potential impact of the project on adjacent
properties from a geotechnical standpoint.
Response 2: The proposed improvements will be constructed within the existing golf course and do
not pose a hazard to adjacent properties from a geotechnical standpoint.
Comment 3: Please provide an updated “Boring Location Map” utilizing a reduced version of the
grading plan for the project as a base map but at a sufficiently large scale to clearly show (at a
minimum): a) the existing limits of the golf course, individual fairways, drainages, and water hazards,
etc., and b) the locations of subsurface exploration. Please note that the “Boring Location map”
presented in the submitted report consists of a Google aerial photograph of the site that is on an
8.5x11” sheet and is at a significantly small scale (approximately 1”=1230’) that results in difficulty
showing the actual locations of the subsurface exploration with respect to the course. Please produce a
map at a scale that is sufficiently large to clearly distinguish the fairways and other features of the golf
course and show the specific locations of the borings on the golf course; a sheet larger than 8.5x11”
will likely be necessary to increase the legibility and show all information.
Response 3: We have utilized the referenced grading plans (Reference 2) Sheets 4 through 22 as a
base map for our Geologic Map presented herein as Figures 1 through 19. This provides the
information at a scale of approximately 1”=93’ when printed on 11 X 17 sheets. The grading plans
depict the existing conditions and the proposed improvements.
Comment 4: Please clarify the range in depth of the existing unsuitable fill and young alluvium for the
areas of the proposed cart paths, bridges, and retaining wall.
Response 4: The depth of fill over alluvium is presented on the Geologic Map next to each boring
location for ease of reference. Generally, based on the boring data, a majority of the golf course has
less than 3 feet of previously placed fill over alluvium. Deeper fill is expected within tee areas, bunker
berms, and hills within the fairways. The improvements proposed for this project include the
realignment of cart paths; the flattening of topography in some localized areas within the Champions
Course to remove small hills and straighten the front of slopes along the perimeter of the course; and
the construction of three 25 ft long cart path or foot bridges. The bridges are expected to be supported
on spread footing foundations. No retaining walls are proposed or depicted on the plans.
Geocon Project No. T2754-22-04 - 3 - REVISED November 21, 2022
Geocon recommends that the fill and upper, unsuitable alluvium be removed to expose competent
alluvium resulting in at least 2 feet of engineered fill beneath the new improvements. Please see section
7.5 in the referenced Limited Geotechnical Investigation report.
Comment 5: As the site is described as underlain by young alluvium and there is no consolidation
testing reported, please provide the basis for the values of potential settlement (total and differential)
for new structures and improvements that are provided in the report.
Response 5: Planned improvements are lightly loaded structures (on the order of 1,500 psf maximum
bearing pressure) with a minimum of 2 feet of compacted fill beneath small footings. Typical
settlement evaluation was performed utilizing static settlement methods (Schmertmann). Since loading
is light and footings are relatively small, the loads will mostly be supported within compacted fill. Only
minor loads will be imposed on saturated clays at depth. Therefore, long term consolidation settlement
evaluation was not considered necessary.
Comment 6: The report indicates liquefaction may be a design consideration for the proposed bridges
and the retaining wall associated with the project. Please further address and clarify the potential for
liquefaction relative to the proposed project and provide recommendations to mitigate, as necessary.
Response 6: There are no retaining walls planned for this project. Slopes at bridges are 2 to 5 feet
high, bridges are single span, lightly loaded and not particularly settlement sensitive. Therefore,
incorporation of liquefaction settlements or lateral movements are considered necessary. Following a
large earthquake event, releveling may be required.
Comment 7: Please clarify the foundation recommendations for the supports for the proposed bridges.
Response 7: The three proposed bridges will be approximately 25-foot-long single spans and will be
either prefabricated or cast in place founded on shallow spread footing foundations. Section 7.7
provides foundation recommendations. In addition, the following is recommended:
Where bridge footings are located next to a descending 3:1 (horizontal:vertical) fill slope or steeper, the
foundations should be extended to a depth where the bottom outside edge of the footing is at least 7
feet horizontally from the face of slope.
Comment 8: Please provide horizontal setback distance from adjacent slopes for foundations
associated with the proposed bridges and the retaining wall.
Response 8: No retaining walls are proposed. The three bridges are proposed in areas where the
topography is relatively flat with no significant slopes in proximity to the bridge locations. The streams
Geocon Project No. T2754-22-04 - 4 - REVISED November 21, 2022
which the bridges span are 2 to 5 feet deep with fairly steep slopes ranging from vertical to
approximately 1;1 (h:v). The additional recommendation provided in Response No. 7 addresses slope
setbacks.
Comment 9: Please address if creep load should be applied to the foundations for the proposed
bridges located adjacent to sloping ground: provide lateral creep load, as necessary.
Response 9: Slopes are 2 to 5 feet, bridges are single span, lightly loaded and not particularly
settlement sensitive. Therefore, evaluation and incorporation of creep loads are considered
unnecessary.
Comment 10: Please provide any recommendations to address the relative shallow groundwater with
respect to the foundations for the proposed bridges or retaining wall, as necessary.
Response 10: There are no retaining walls proposed for this project. Groundwater is shallow at the site
and bridge foundation excavations could encounter groundwater. If encountered, groundwater should
be pumped from the excavation and the excavation bottom stabilized if not firm and unyielding as with
typical grading operations.
Comment 11: Please clarify if reinforcing is recommended for all hardscape improvements due to the
expansive soils and underlying young alluvium.
Response 11: Per Section 7.8.1 of the referenced Limited Geotechnical Investigation report, Geocon
recommends that concrete flatwork be reinforced with No. 3 bars placed 24 inches on center.
Comment 12: As the results of Expansion Index testing presented in the report indicate a medium
expansion potential (EI=74 to 78), please provide recommendations as necessary and a statement that
the proposed foundation system/slabs-on-grade will meet the requirements of section 1808.6 of the
2019 California Building Code. As soils with expansion index (EI) over 20 are considered expansive
and require mitigation in accordance with sections 1803.5.3 and 1808.6 of the 2019 CBC, please
indicate the method of section 1808.6 (1808.6.1 through 1808.6.4) that is being recommended to satisfy
the requirement and provide the Effective Plasticity Index and any other parameters for foundation
design in accordance with WRI/CRSI Design of Slab-on-Ground floors, as necessary.
Response 12: Since the expansive soils will not be removed, stabilization will be required.
Stabilization will consist of removing existing expansive soils beneath footings, wetting (presaturating)
and placing as compacted fill. No slabs-on-grade are proposed for this project.
Comment 13: Soluble sulfate testing presented in the report indicates both moderate and severs [sic]
sulfate exposure (S1 and S2). Consequently, please provide recommendations for sulfate resistant
Geocon Project No. T2754-22-04 - 5 - REVISED November 21, 2022
concrete (compressive strength, w/c ratio, type cement) consistent with the 2019 California Building
Code and ACI 318, Tables 4.2.1 and 4.3.1 assuming “Severe” (S2) exposure class.
Response 13: The Exposure Class with corresponding Cement Type, Water to Cement Ratio, and
Minimum Compressive Strength are presented in Table 7.2.5 of the referenced Limited Geotechnical
Investigation report.
Comment 14: Please provide the OSHA Type Soil (A, B, or C) and associated temporary slope
inclination (H:V) that the construction plans and contractors should adhere to during the design and
construction of the development.
Response 14: Geocon presents recommendations for temporary excavations in Section 7.4 of
Reference 3. The site soils should be considered as Class C with the addition of saturation. Conditions
can vary within excavations and Geocon may not be present during all site work, therefore the
contractor’s competent person should provide specific recommendations for excavation in accordance
with OSHA requirements.
Comment 15: Please provide a complete summary list of the geotechnical observation and testing
services that should be performed as part of the construction of this proposed development.
Response 15: Geocon should provide geotechnical testing and observation services during the grading
operations, foundation construction, utility installation, retaining wall backfill and pavement
installation. Table 1 presents the typical geotechnical observations we would expect for the proposed
improvements.
TABLE 1
EXPECTED GEOTECHNICAL TESTING AND OBSERVATION SERVICES
Construction Phase Observations Expected Time Frame
Ground Modification Ground Modification Installation Full Time
Confirmation Testing Part Time to Full Time
Grading
Base of Removal Part Time During
Removals
Geologic Logging Part Time to Full Time
Fill Placement and Soil Compaction Full Time
Soldier Piles Solder Pile Drilling Depth Part Time
Tieback Anchors Tieback Drilling and Installation Full Time
Tieback Testing Full Time
Soil Nail Walls Soil Nail Drilling and Installation Full Time
Soil Nail Testing Full Time
Foundations Foundation Excavation Observations Full Time
Drilling Operations for Piles Part Time
Geocon Project No. T2754-22-04 - 6 - REVISED November 21, 2022
Utility Backfill Fill Placement and Soil Compaction Part Time to Full Time
Retaining Wall Backfill Fill Placement and Soil Compaction Part Time to Full Time
Subgrade for Sidewalks, Curb/Gutter
and Pavement Soil Compaction Part Time
Pavement Construction
Base Placement and Compaction Part Time
Asphalt Concrete Placement and
Compaction Full Time
LIMITATIONS
The recommendations of this report pertain only to the subject site and are based upon the assumption
that the soil conditions do not deviate from those disclosed in this and Geocon’s 2021 report. If any
variations or undesirable conditions are encountered during construction, or if the proposed
construction will differ from that expected herein, Geocon West, Inc. 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 West, Inc.
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.
The findings of this report are valid as of the date of this report. However, changes in the 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.
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 presented 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. T2754-22-04 - 7 - REVISED November 21, 2022
If you have any 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.
Lisa A. Battiato
CEG 2316
Joseph J. Vettel
GE 2401
Attachments: Geotechnical Report Review dated September 28, 2022
Figures 1 through 19, Geologic Map
Distribution: (pdf) Addressee
(pdf) Mr. Keith Hansen, O’Day Consultants
PROJECT NO. T754-22-04 FIG. 1
CHAMPIONS COURSE RENOVATIONSOMNI LA COSTA RESORT & SPA
2100 COSTA DEL MAR ROAD
CARLSBAD, CALIFORNIA
GEOLOGIC MAP
HD OCTOBER 2022
Source: O’Day Consultants, Rough Grading Plan for Omni Resort Golf Course, prepared September 1, 2022.
……GROUNDWATER
ENCOUNTERED
3.5’
GEOCON LEGEND
Locations are approximate
B-6 ……. GEOCON BORING
LOCATION (2021)
Qya .…. YOUNG ALLUVIAL
DEPOSITS
afu …...UNDOCUMENTED
FILL
B-8 ……. GEOCON BORING
LOCATION (2002)
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PROJECT NO. T754-22-04 FIG. 2
CHAMPIONS COURSE RENOVATIONSOMNI LA COSTA RESORT & SPA
2100 COSTA DEL MAR ROAD
CARLSBAD, CALIFORNIA
GEOLOGIC MAP
HD OCTOBER 2022
Source: O’Day Consultants, Rough Grading Plan for Omni Resort Golf Course, prepared September 1, 2022.
B-7 ½ -5’ Qya
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0 -½’ afu
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GEOCON LEGEND
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PROJECT NO. T754-22-04 FIG. 3
CHAMPIONS COURSE RENOVATIONSOMNI LA COSTA RESORT & SPA
2100 COSTA DEL MAR ROAD
CARLSBAD, CALIFORNIA
GEOLOGIC MAP
HD OCTOBER 2022
Source: O’Day Consultants, Rough Grading Plan for Omni Resort Golf Course, prepared September 1, 2022.
B-5 1-5’ Qya
(SM)
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ENCOUNTERED
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GEOCON LEGEND
Locations are approximate
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LOCATION (2021)
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DEPOSITS
afu …...UNDOCUMENTED
FILL
B-8 ……. GEOCON BORING
LOCATION (2002)
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GEOTECHNICAL, ENVIRONMENTAL, MATERIALS
41571 CORNING PLACE #101, MURRIETA, CALIFORNIA 92562
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PROJECT NO. T754-22-04 FIG. 4
CHAMPIONS COURSE RENOVATIONSOMNI LA COSTA RESORT & SPA
2100 COSTA DEL MAR ROAD
CARLSBAD, CALIFORNIA
GEOLOGIC MAP
HD OCTOBER 2022
Source: O’Day Consultants, Rough Grading Plan for Omni Resort Golf Course, prepared September 1, 2022.
B-3 ½ -5’ Qya
(SM)
0 -½’ afu
Qya
……GROUNDWATER
ENCOUNTERED
3.5’
GEOCON LEGEND
Locations are approximate
B-6 ……. GEOCON BORING
LOCATION (2021)
Qya .…. YOUNG ALLUVIAL
DEPOSITS
afu …...UNDOCUMENTED
FILL
B-8 ……. GEOCON BORING
LOCATION (2002)
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PROJECT NO. T754-22-04 FIG. 5
CHAMPIONS COURSE RENOVATIONSOMNI LA COSTA RESORT & SPA
2100 COSTA DEL MAR ROAD
CARLSBAD, CALIFORNIA
GEOLOGIC MAP
HD OCTOBER 2022
Source: O’Day Consultants, Rough Grading Plan for Omni Resort Golf Course, prepared September 1, 2022.
……GROUNDWATER
ENCOUNTERED
3.5’
GEOCON LEGEND
Locations are approximate
B-6 ……. GEOCON BORING
LOCATION (2021)
Qya .…. YOUNG ALLUVIAL
DEPOSITS
afu …...UNDOCUMENTED
FILL
B-8 ……. GEOCON BORING
LOCATION (2002)
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GEOCON
W E S T , I N C .
GEOTECHNICAL, ENVIRONMENTAL, MATERIALS
41571 CORNING PLACE #101, MURRIETA, CALIFORNIA 92562
1
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PROJECT NO. T754-22-04 FIG. 6
CHAMPIONS COURSE RENOVATIONSOMNI LA COSTA RESORT & SPA
2100 COSTA DEL MAR ROAD
CARLSBAD, CALIFORNIA
GEOLOGIC MAP
HD OCTOBER 2022
Source: O’Day Consultants, Rough Grading Plan for Omni Resort Golf Course, prepared September 1, 2022.
……GROUNDWATER
ENCOUNTERED
3.5’
GEOCON LEGEND
Locations are approximate
B-6 ……. GEOCON BORING
LOCATION (2021)
Qya .…. YOUNG ALLUVIAL
DEPOSITS
afu …...UNDOCUMENTED
FILL
B-8 ……. GEOCON BORING
LOCATION (2002)
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PROJECT NO. T754-22-04 FIG. 7
CHAMPIONS COURSE RENOVATIONSOMNI LA COSTA RESORT & SPA
2100 COSTA DEL MAR ROAD
CARLSBAD, CALIFORNIA
GEOLOGIC MAP
HD OCTOBER 2022
Source: O’Day Consultants, Rough Grading Plan for Omni Resort Golf Course, prepared September 1, 2022.
……GROUNDWATER
ENCOUNTERED
3.5’
GEOCON LEGEND
Locations are approximate
B-6 ……. GEOCON BORING
LOCATION (2021)
Qya .…. YOUNG ALLUVIAL
DEPOSITS
afu …...UNDOCUMENTED
FILL
B-8 ……. GEOCON BORING
LOCATION (2002)
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W E S T , I N C .
GEOTECHNICAL, ENVIRONMENTAL, MATERIALS
41571 CORNING PLACE #101, MURRIETA, CALIFORNIA 92562
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PROJECT NO. T754-22-04 FIG. 8
CHAMPIONS COURSE RENOVATIONSOMNI LA COSTA RESORT & SPA
2100 COSTA DEL MAR ROAD
CARLSBAD, CALIFORNIA
GEOLOGIC MAP
HD OCTOBER 2022
Source: O’Day Consultants, Rough Grading Plan for Omni Resort Golf Course, prepared September 1, 2022.
B-6 1 -5’ Qya
(SM)
0 –1’ afu
Qya
……GROUNDWATER
ENCOUNTERED
3.5’
GEOCON LEGEND
Locations are approximate
B-6 ……. GEOCON BORING
LOCATION (2021)
Qya .…. YOUNG ALLUVIAL
DEPOSITS
afu …...UNDOCUMENTED
FILL
B-8 ……. GEOCON BORING
LOCATION (2002)
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W E S T , I N C .
GEOTECHNICAL, ENVIRONMENTAL, MATERIALS
41571 CORNING PLACE #101, MURRIETA, CALIFORNIA 92562
o· 10· 40'
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SCALE: 1' = 40'
PROJECT NO. T754-22-04 FIG. 9
CHAMPIONS COURSE RENOVATIONSOMNI LA COSTA RESORT & SPA
2100 COSTA DEL MAR ROAD
CARLSBAD, CALIFORNIA
GEOLOGIC MAP
HD OCTOBER 2022
Source: O’Day Consultants, Rough Grading Plan for Omni Resort Golf Course, prepared September 1, 2022.
……GROUNDWATER
ENCOUNTERED
3.5’
GEOCON LEGEND
Locations are approximate
B-6 ……. GEOCON BORING
LOCATION (2021)
Qya .…. YOUNG ALLUVIAL
DEPOSITS
afu …...UNDOCUMENTED
FILL
B-8 ……. GEOCON BORING
LOCATION (2002)
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PROJECT NO. T754-22-04 FIG. 10
CHAMPIONS COURSE RENOVATIONSOMNI LA COSTA RESORT & SPA
2100 COSTA DEL MAR ROAD
CARLSBAD, CALIFORNIA
GEOLOGIC MAP
HD OCTOBER 2022
Source: O’Day Consultants, Rough Grading Plan for Omni Resort Golf Course, prepared September 1, 2022.
……GROUNDWATER
ENCOUNTERED
3.5’
GEOCON LEGEND
Locations are approximate
B-6 ……. GEOCON BORING
LOCATION (2021)
Qya .…. YOUNG ALLUVIAL
DEPOSITS
afu …...UNDOCUMENTED
FILL
B-8 ……. GEOCON BORING
LOCATION (2002)
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APN 215-220-05
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GEOCON
W E S T , I N C .
GEOTECHNICAL, ENVIRONMENTAL, MATERIALS
41571 CORNING PLACE #101, MURRIETA, CALIFORNIA 92562
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SCALE: 1. = 40'
PROJECT NO. T754-22-04 FIG. 11
CHAMPIONS COURSE RENOVATIONSOMNI LA COSTA RESORT & SPA
2100 COSTA DEL MAR ROAD
CARLSBAD, CALIFORNIA
GEOLOGIC MAP
HD OCTOBER 2022
……GROUNDWATER
ENCOUNTERED
3.5’
Source: O’Day Consultants, Rough Grading Plan for Omni Resort Golf Course, prepared September 1, 2022.
GEOCON LEGEND
Locations are approximate
B-6 ……. GEOCON BORING
LOCATION (2021)
Qya .…. YOUNG ALLUVIAL
DEPOSITS
afu …...UNDOCUMENTED
FILL
B-8
B-7 1½ -5’ Qya
(CL)
0 -1½’ afu
Qya ……. GEOCON BORING
LOCATION (2002)
3.5’
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W E S T , I N C .
GEOTECHNICAL, ENVIRONMENTAL, MATERIALS
41571 CORNING PLACE #101, MURRIETA, CALIFORNIA 92562
i
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SCALE, I" = 40'
PROJECT NO. T754-22-04 FIG. 12
CHAMPIONS COURSE RENOVATIONSOMNI LA COSTA RESORT & SPA
2100 COSTA DEL MAR ROAD
CARLSBAD, CALIFORNIA
GEOLOGIC MAP
HD OCTOBER 2022
Source: O’Day Consultants, Rough Grading Plan for Omni Resort Golf Course, prepared September 1, 2022.
……GROUNDWATER
ENCOUNTERED
3.5’
GEOCON LEGEND
Locations are approximate
B-6 ……. GEOCON BORING
LOCATION (2021)
Qya .…. YOUNG ALLUVIAL
DEPOSITS
afu …...UNDOCUMENTED
FILL
B-8
B-7 2 ½ -16 ½ ’
Qya (SC & CL)
0 –2 ½’ afu
Qya
……. GEOCON BORING
LOCATION (2002)
8’
B-6
2 -16 ½ ’ Qya
(CL)
0 –2 afu
Qya3.5’
APN I 216-600-05
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GEOCON
W E S T , I N C .
GEOTECHNICAL ENVIRONME
41571 CORNING PLACE #101, MURRIET'::'.~~!:L.1~'i~l~R~~~;
i o· JO' 40'
5 20
SCALE: I• = 40'
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PROJECT NO. T754-22-04 FIG. 13
CHAMPIONS COURSE RENOVATIONSOMNI LA COSTA RESORT & SPA
2100 COSTA DEL MAR ROAD
CARLSBAD, CALIFORNIA
GEOLOGIC MAP
HD OCTOBER 2022
Source: O’Day Consultants, Rough Grading Plan for Omni Resort Golf Course, prepared September 1, 2022.
……GROUNDWATER
ENCOUNTERED
3.5’
GEOCON LEGEND
Locations are approximate
B-6 ……. GEOCON BORING
LOCATION (2021)
Qya .…. YOUNG ALLUVIAL
DEPOSITS
afu …...UNDOCUMENTED
FILL
B-8 ……. GEOCON BORING
LOCATION (2002)\
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0' 10' 40'
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PROJECT NO. T754-22-04 FIG. 14
CHAMPIONS COURSE RENOVATIONSOMNI LA COSTA RESORT & SPA
2100 COSTA DEL MAR ROAD
CARLSBAD, CALIFORNIA
GEOLOGIC MAP
HD OCTOBER 2022
Source: O’Day Consultants, Rough Grading Plan for Omni Resort Golf Course, prepared September 1, 2022.
……GROUNDWATER
ENCOUNTERED
3.5’
GEOCON LEGEND
Locations are approximate
B-6 ……. GEOCON BORING
LOCATION (2021)
Qya .…. YOUNG ALLUVIAL
DEPOSITS
afu …...UNDOCUMENTED
FILL
B-8
B-4 0 –16 ½ ’
Qya (CL)
Qya
……. GEOCON BORING
LOCATION (2002)
3.5’
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GEOCON
W E S T , I N C .
GEOTECHNICAL, ENVIRONMENTAL, MATERIALS
41571 CORNING PLACE #101, MURRIETA, CALIFORNIA 92562
i
O' 10' 40'
D
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SCALE, 1" = 40'
PROJECT NO. T754-22-04 FIG. 15
CHAMPIONS COURSE RENOVATIONSOMNI LA COSTA RESORT & SPA
2100 COSTA DEL MAR ROAD
CARLSBAD, CALIFORNIA
GEOLOGIC MAP
HD OCTOBER 2022
Source: O’Day Consultants, Rough Grading Plan for Omni Resort Golf Course, prepared September 1, 2022.
……GROUNDWATER
ENCOUNTERED
3.5’
GEOCON LEGEND
Locations are approximate
B-6 ……. GEOCON BORING
LOCATION (2021)
Qya .…. YOUNG ALLUVIAL
DEPOSITS
afu …...UNDOCUMENTED
FILL
B-8
B-7 0 –16 ½ ’ Qya
(SM & CL)
Qya
……. GEOCON BORING
LOCATION (2002)
4’
1-19 ½ ’
Qya (CL)
0 -1 afu
Qya
B-1
7.2’
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41571 CORNING PLACE #101, MURRIETA, CALIFORNIA 92562
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PROJECT NO. T754-22-04 FIG. 16
CHAMPIONS COURSE RENOVATIONSOMNI LA COSTA RESORT & SPA
2100 COSTA DEL MAR ROAD
CARLSBAD, CALIFORNIA
GEOLOGIC MAP
HD OCTOBER 2022
Source: O’Day Consultants, Rough Grading Plan for Omni Resort Golf Course, prepared September 1, 2022.
……GROUNDWATER
ENCOUNTERED
3.5’
GEOCON LEGEND
Locations are approximate
B-6 ……. GEOCON BORING
LOCATION (2021)
Qya .…. YOUNG ALLUVIAL
DEPOSITS
afu …...UNDOCUMENTED
FILL
B-8 ……. GEOCON BORING
LOCATION (2002)
l
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'10' 40'
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GEOTECHNICAL, ENVIRONMENTAL, MATERIALS
41571 CORNING PLACE #101, MURRIETA, CALIFORNIA 92562
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PROJECT NO. T754-22-04 FIG. 17
CHAMPIONS COURSE RENOVATIONSOMNI LA COSTA RESORT & SPA
2100 COSTA DEL MAR ROAD
CARLSBAD, CALIFORNIA
GEOLOGIC MAP
HD OCTOBER 2022
Source: O’Day Consultants, Rough Grading Plan for Omni Resort Golf Course, prepared September 1, 2022.
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PROJECT NO. T754-22-04 FIG. 18
CHAMPIONS COURSE RENOVATIONSOMNI LA COSTA RESORT & SPA
2100 COSTA DEL MAR ROAD
CARLSBAD, CALIFORNIA
GEOLOGIC MAP
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Source: O’Day Consultants, Rough Grading Plan for Omni Resort Golf Course, prepared September 1, 2022.
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GEOTECHNICAL, ENVIRONMENTAL, MATERIALS
41571 CORNING PLACE #101, MURRIETA, CALIFORNIA 92562
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PROJECT NO. T754-22-04 FIG. 19
CHAMPIONS COURSE RENOVATIONSOMNI LA COSTA RESORT & SPA
2100 COSTA DEL MAR ROAD
CARLSBAD, CALIFORNIA
GEOLOGIC MAP
HD OCTOBER 2022
Source: O’Day Consultants, Rough Grading Plan for Omni Resort Golf Course, prepared September 1, 2022.
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ENCOUNTERED
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Locations are approximate
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LOCATION (2021)
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W E S T , I N C .
GEOTECHNICAL, ENVIRONMENTAL, MATERIALS
41571 CORNING PLACE #101, MURRIETA, CALIFORNIA 92562
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Project No. T2754-22-04A
January 27, 2023
REVISED February 17, 2023
LC Investments 2010, LLC
d/b/a Omni La Costa Resort & Spa
4001 Maple Avenue, Suite 300
Dallas, Texas 75219
Attention: Mr. Clint Gulick
Subject: STRUCTURAL PLAN REVIEW
OMNI LA COSTA CHAMPIONS COURSE RENOVATION
CARLSBAD, CALIFORNIA
References: 1. Structural Plan, Sheets 3 through 5, Job No. 382.008-22, Revision Date February
16, 2023, prepared by Orie2 Engineering.
3. Limited Geotechnical Investigation, Champions Course Renovations, Omni La
Costa Resort & Spa, 2100 Costa Del Mar Road, Carlsbad, California, Project T2754-
22-04, dated April 15, 2021, prepared by Geocon West, Inc.
Mr. Gulick:
In accordance with the request of O’Day Consultants, Geocon West, Inc. (Geocon) has prepared this
letter to provide a summary of our geotechnical review of the referenced project structural plan
(Reference No. 1), with respect to our geotechnical investigation report (Reference No. 2).
The referenced structural plan is in general conformance with the geotechnical parameters and
recommendations provided in our referenced reporting. Our review was limited to the geotechnical
aspects of project development and does not include review of other details on the referenced plan.
Should you have any 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.
Andrew T. Shoashekan
PE 93940
Lisa A. Battiato
CEG 2316
ATS:LAB
Distribution: (clint.gulick@omnihotels.com) Addressee
(keithh@odayconsultants.com) Keith Hansen
GEOCON
W E S T, I N C.
GEOTECHNICAL ■ENVIRONMENTAL ■ MATERIALS
41571 Corning Place, Suite l 01 ■ Murrieto, Colifornia 92562-7065 ■ Telephone 951 .304.2300 ■ Fox 951.304.2392
Project No. T2754-22-04a
July 20, 2023
LC Investments 2010, LLC
d/b/a Omni La Costa Resort & Spa
4001 Maple Avenue, Suite 300
Dallas, Texas 75219
Attention: Mr. Clint Gulick
Subject: STORM WATER MANAGEMENT INVESTIGATION
OMNI LA COSTA GOLF COURSE
2100 COSTA DEL MAR ROAD
CARLSBAD, CALIFORNIA
References:
1. Limited Geotechnical Investigation, Champions Course Renovations, Omni La Costa
Resort & Spa, 2100 Costa Del Mar Road, Carlsbad, California, prepared by Geocon
West Incorporated, dated April 15, 2021 (Project No. T2754-22-04.
2. Infiltration Testing & Pervious Paving Recommendations, Omni La Costa Resort &
Spa, 2100 Costa Del Mar Road, Carlsbad, California, prepared by Geocon West
Incorporated, dated August 2, 2022 (Project No. T2754-22-06).
3. Infiltration Testing and Pavement Recommendations, Omni La Costa Resort & Spa,
2100 Costa Del Mar Road, Carlsbad, California, prepared by Geocon West
Incorporated, dated September 26, 2022 (Project No. T2754-22-06).
4. Infiltration Test Report, Omni La Costa Resort & Spa, 2100 Costa Del Mar Road,
Carlsbad, California, prepared by Geocon West Incorporated, dated March 21, 2023
(Project No. T2754-22-06).
Dear Mr. Gulick:
Geocon West, Inc. (Geocon) has compiled this report to provide an updated summayry of multiple infiltration
studies performed in associateion with the Champions Course and Driving Range renovations at Omni La
Costa Resort and Spa in Carlsbad, California. This information updates the previous work and presents our
findings in accordance with City of Carlsbad BMP Design Manual (2023).
SITE AND PROJECT DESCRIPTION
The renovations with new BMPs will occur in three areas within the southwestern area of the La Costa Resort
Property: northeast of the intersection of Costa Del Mar Road and El Camino Real; between the golf course
parking lot and San Marcos Creek; and southeast of the intersection of Estrella Del Mar Road and Arenal
Road. The site areas are occupied by landscaped areas and parking lots.
GEOCON
W E S T , I N C.
GEOTECHNI CAL ■ ENVIRONMENTAL ■ MATERIALS O
STORM WATER MANAGEMENT INVESTIGATION
We understand storm water management devices will be used in accordance with the 2023 City of Carlsbad
BMP Design Manual. If not properly constructed, there is a potential for distress to improvements and
properties located hydrologically down gradient or adjacent to these devices. 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 hydrogeological study at the site. If infiltration of storm
water runoff occurs, downstream properties may be subjected to seeps, springs, slope instability, raised
groundwater, movement of foundations and slabs, or other undesirable impacts as a result of water infiltration.
Hydrologic Soil Group
The United States Department of Agriculture (USDA), Natural Resources Conservation Services, possesses
general information regarding the existing soil conditions for areas within the United States. The USDA
website also provides the Hydrologic Soil Group. Table 1 presents the descriptions of the hydrologic soil
groups. If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is for drained areas
and the second is for undrained areas. In addition, the USDA website also provides an estimated saturated
hydraulic conductivity for the existing soil.
TABLE 1
HYDROLOGIC SOIL GROUP DEFINITIONS
Soil Group Soil Group Definition
A
Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist
mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a
high rate of water transmission.
B
Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately
deep or deep, moderately well drained or well drained soils that have moderately fine texture to
moderately coarse texture. These soils have a moderate rate of water transmission.
C
Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a
layer that impedes the downward movement of water or soils of moderately fine texture or fine
texture. These soils have a slow rate of water transmission.
D
Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These
consist chiefly of clays that have a high shrink-swell potential, soils that have a high water
table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow
over nearly impervious material. These soils have a very slow rate of water transmission.
Table 2 presents the information from the USDA website for the subject property. The Hydrologic Soil Group
Map presents output from the USDA website showing the limits of the soil units.
TABLE 2
USDA WEB SOIL SURVEY – HYDROLOGIC SOIL GROUP*
Map Unit Name Map Unit Symbol
Approximate Percentage of Property
Hydrologic Soil Group
kSAT of Most Limiting Layer (micrometers/second)
Northeast of Intersection of Costa Del Mar Road and El Camino Real
Huerhuero land complex, 2 to 9 percent slopes HuC 90 D 2.0070
Salinas Clay Loam,
2 to 9 percent slopes SbC 10 D 2.7000
Between Golf Course Parking Lot and San Marcos Creek
Tidal Flats Tf 20 D --
Salinas Clay Loam, 2 to 9 percent slopes SbC 80 D 2.7000
Southeast of Arenal Road and Estrella Del Mar Road
HuerHuero land complex, 9 to 30 percent slopes HuE 100 D 1.9291
*The areas of the property that possess fill materials should be considered to possess a Hydrologic Soil Group D.
Hydrologic Soil Group Map
In Situ Testing
We performed 2 constant-head infiltration tests using the Aardvark permeameter at each of the proposed BMP
locations. P-1 and P-2 were performed between the golf course parking lot and San Marcos Creek; P-3 and P-4
were performed northeast of El Camino Real and Costa Del Mar Road; and P-5 through P-8 were performed at
two locations within the parking lot southeast of Arenal Road and Estrella Del Mar Road. The site location maps
and infiltration data sheets are presented in the referenced reports. Table 3 presents the results of the infiltration
tests. The field data sheets are attached herein. We applied a feasibility factor of safety of 2.0 to our estimated
infiltration rates. The designer of storm water devices should apply an appropriate factor of safety, where
necessary. Soil infiltration rates from in-situ tests can vary significantly from one location to another due to the
heterogeneous characteristics inherent to most soil.
TABLE 3
INFILTRATION TEST RESULTS
Test No. Geologic Unit
Test Depth (feet, below grade)
Field-Saturated Hydraulic Conductivity/Infiltration Rate, ksat (inch/hour)
Worksheet Infiltration Rate1 (inch/hour)
Infiltration Category
P-1 Qya 3 0.001 0.000 No Infiltration
P-2 Qya 3 0.001 0.000 No Infiltration
Average: 0.001 0.000
P-3 Qoa 9 2.400 1.200 Full Infiltration
P-4 Qoa 9 1.000 0.500 Full Infiltration
Average: 1.700 0.850
P-5 & P-6 Basin Moved – P-5 and P-6 no longer pertinent
P-7 Qoa 4 0.019 0.075 Partial Infiltration
P-8 Qoa 4 0.010 0.037 No Infiltration
Average: 0.145 0.056
1 Using a Factor of Safety of 2.
Infiltration categories include full infiltration, partial infiltration and no infiltration. Table 4 presents the
commonly accepted definitions of the potential infiltration categories based on the infiltration rates.
TABLE 4 INFILTRATION CATEGORIES
Infiltration Category Field Infiltration Rate, I
(Inches/Hour)
Factored Infiltration Rate1, I
(Inches/Hour)
Full Infiltration I > 1.0 I > 0.5
Partial Infiltration 0.10 < I < 1.0 0.05 < I < 0.5
No Infiltration (Infeasible) I < 0.10 I < 0.05
1 Using a Factor of Safety of 2.
“Full Infiltration” should be considered for the basin northeast of El Camino Real and Costa Del Mar Road.
“Partial Infiltration” should be considered for the proposed basin southeast of Arenal Road and Estrella Del
Mar Road. “No Infiltration” should be considered for the area between the golf course parking lot and San
Marcos Creek.
GEOTECHNICAL CONSIDERATIONS
Groundwater Elevations
We did not encounter groundwater during the 20-foot-deep borings for the basin northeast of El Camino Real
and Costa Del Mar Road or for the parking lot southeast of Arenal Road and Estrella Del Mar Road. We did
not encounter groundwater within 13 feet of existing ground between the golf course parking lot and San
Marcos Creek. We expect permanent groundwater is approximately 40 feet below the existing ground surface.
New or Existing Utilities
No utilities are present within the El Camino Real/Costa Del Mar basin property. A sewer main is present
near the proposed basin at Arenal /Estrella Del Mar Roads. Electrical utilities are present between the golf
course parking lot and San Marcos Creek. Full or partial infiltration should not be allowed in the areas of the
utilities to help prevent potential damage/distress to improvements. Mitigation measures to prevent water from
infiltrating the utilities consist of setbacks, installing cutoff walls around the utilities and installing subdrains
and/or installing liners.
Existing Structures
Structures are located more than 100 feet from the proposed infiltration BMPs. Water should not be allowed
to infiltrate in areas where it could affect the existing and neighboring properties and existing and adjacent
structures, improvements and roadways. Mitigation for existing structures consist of not allowing water
infiltration within a 1:1 plane from existing foundations and extending the infiltration areas at least 10 feet
from the existing foundations and into formational materials.
Soil or Groundwater Contamination
We are unaware of contaminated soil on the property. Therefore, infiltration associated with this risk is
considered feasible.
Hydrocollapse
The Older and Younger Alluvium may have the potential for hydrocollapse. Therefore, full or partial
infiltration should be considered infeasible.
CONCLUSIONS AND RECOMMENDATIONS
Storm Water Evaluation Narrative and Conclusion
The basins in the two parking lot areas will be in Older Alluvium. This unit was found to have partial to full
infiltration. However, a sewer line is present near the basin at Arenal/Estrella Del Mar Roads which
necessitates lining of that basin to prevent infiltration. Infiltration at Ela Camino Real/Costa Del Mar Road is
feasible. Infiltration between the golf course parking lot and San Marcos Creek is not feasible due to the lack
of infiltration within the Younger Alluvium.
Storm Water Management Devices
Liners and subdrains should be incorporated into the design and construction of the planned storm water
devices. The liners should be impermeable (e.g. High-density polyethylene, HDPE, with a thickness of about
30 mil or equivalent Polyvinyl Chloride, PVC) to prevent water migration. The subdrains should be perforated
within the liner area, installed at the base and above the liner, be at least 3 inches in diameter and consist of
Schedule 40 PVC pipe. The subdrains outside of the liner should consist of solid pipe. The penetration of the
liners at the subdrains should be properly waterproofed. The subdrains should be connected to a proper outlet.
The devices should also be installed in accordance with the manufacturer’s recommendations.
Storm Water Standard Worksheets
We evaluated the proposed project with respect to the infiltration restrictions contained in Table D.1-1 in
Appendix D of the City of Carlsbad BMP Design Manual (see Table 5).
TABLE 5
CONSIDERATIONS FOR GEOTECHNICAL ANALYSIS OF INFILTRATION RESTRICTIONS
(TABLE D.1-1 OF APPENDIX D)
Restriction Element
Is Element Applicable? (Yes/No)
Mandatory
Considerations
BMP is within 100’ of Contaminated Soils No
BMP is within 100’ of Industrial Activities Lacking Source Control No
BMP is within 100’ of Well/Groundwater Basin No
BMP is within 50’ of Septic Tanks/Leach Fields No
BMP is within 10’ of Structures/Tanks/Walls No
BMP is within 10’ of Sewer Utilities Yes 1
BMP is within 10’ of Groundwater Table No
BMP is within Hydric Soils No
BMP is within Highly Liquefiable Soils and has Connectivity to Structures No
BMP is within 1.5 Times the Height of Adjacent Steep Slopes (≥25%) No
City Staff has Assigned “Restricted” Infiltration Category No
Restriction Element
Is Element
Applicable? (Yes/No)
Optional Considerations
BMP is within Predominantly Type D Soil Yes
BMP is within 10’ of Property Line No
BMP is within Fill Depths of ≥5’ (Existing or Proposed) No
BMP is within 10’ of Underground Utilities Yes 1
BMP is within 250’ of Ephemeral Stream Yes 2
Other (Provide detailed geotechnical support) – Hydrocollapse (See discussion herein) Yes
Result
Based on examination of the best available information, I have not identified any restrictions above.
Based on examination of the best available information, I have identified one or more restrictions above. X Restricted
1 Applicable to Arenal Road/Estrella Del Mar Road; not applicable to El Camino Real/Costa Del Mar Road
or golf course parking lot areas.
2 Applicable to area between golf course and San Marcos Creek.
The BMP manual also has a worksheet (Table D.2-4 of Appendix D) that helps the project civil engineer
estimate the factor of safety based on several factors. Table 6 describes the suitability assessment input
parameters related to the geotechnical engineering aspects for the factor of safety determination.
TABLE 6
GUIDANCE FOR DETERMINING INDIVIDUAL FACTOR VALUES – PART A
(TABLE D.2-4 OF APPENDIX D)
Consideration High Concern – 3 Points Medium Concern – 2 Points Low Concern – 1 Point
Infiltration Test Method Any At least 2 tests of any kind within 50’ of BMP
At least 4 tests within BMP footprint, OR Large/Small Scale Pilot Infiltration Testing over at least 5% of BMP footprint.
Soil Texture Class Unknown, Silty, or Clayey Loamy Granular/Slightly Loamy
Site Variability Unknown or High Moderately Homogenous Significantly
Homogenous
Depth to Groundwater/ Obstruction <5’ below BMP 5-15’ below BMP >15’ below BMP
Table 7 presents the estimated safety factor values for the evaluation of the factor of safety. This table only
presents the suitability assessment safety factor (Part A) of the worksheet. The project civil engineer should
evaluate the safety factor for design (Part B) and use the combined safety factor for the design infiltration rate.
TABLE 7
DETERMINATION OF SAFETY FACTOR
(TABLE D.2-3 OF APPENDIX D)
Consideration Assigned Weight (w) Factor Value (v) Product (p = w x v)
Suitability
Assessment
(A)
Infiltration Testing Method 0.25 2 0.50
Soil Texture Class 0.25 2 0.50
Site Variability 0.25 3 0.75
Depth to Groundwater/Obstruction 0.25 1 0.25
Suitability Assessment Safety Factor, SA = p 2.0
Design (B)
Pretreatment * Refer to Table D.2-4
*
Resiliency * *
Compaction * *
Design Safety Factor, SB = p *
Safety Factor, S = SA x SB (Must be always greater than or equal to 2) *
*The civil engineer should evaluate the “Design (B)” factors and the Safety Factor, S.
Table 8 presents the elements for determining the design infiltration rate (Table D.2-1 of Appendix D). The
civil engineer should evaluate the Safety Factor, S and Design Infiltration Rate. We also included herein the
original I-8 Form from previous submittals for consistency with the current submittal process.
TABLE 8
ELEMENTS FOR DETERMINATION OF DESIGN INFILTRATION RATES
Item Value
Initial Infiltration Rate
Identify per Section D.2.1
El Cme Real/Costa Del Mar Rd 0.850 Inches/Hour
Arenal/Estrella Del Mar Rds 0.056 Inches/Hour
Golf Course Pkg Lot/San Marcos
Creek 0.000 Inches/Hour
Corrected Infiltration Rate
Identify per Section D.2.2
El Cme Real/Costa Del Mar Rd 0.425 Inches/Hour
Arenal/Estrella Del Mar Rds 0.028 Inches/Hour
Golf Course Pkg Lot/San Marcos
Creek 0.000 Inches/Hour
Safety Factor
Identify per Section D.2.3
*
Design Infiltration Rate
Corrected Infiltration Rate/Safety
Factor
*Inches/Hour
*The civil engineer should evaluate the Safety Factor and Design Infiltration Rate.
If you have any questions regarding this correspondence, or if we may be of further service, please contact the
undersigned at your convenience.
Very truly yours,
GEOCON WEST, INC.
Lisa Battiato
CEG 2316
Joseph J. Vettel
GE 2401
LAB:JJV:hd
Attachment: Form I-8
Appendix C: Geotechnical and Groundwater Investigation Requirements
C-1 July 2018
Worksheet C.4-1: Categorization of Infiltration Feasibility Condition
Categorization of Infiltration Feasibility Condition Worksheet C.4-1
Part 1 - Full Infiltration Feasibility Screening Criteria
Would infiltration of the full design volume be feasible from a physical perspective without any undesirable
consequences that cannot be reasonably mitigated?
Note that it is not necessary to investigate each and every criterion in the worksheet if infiltration is
precluded. Instead a letter of justification from a geotechnical professional familiar with the local conditions
substantiating any geotechnical issues will be required.
Criteria Screening Question Yes No
1
Is the estimated reliable infiltration rate below proposed facility
locations greater than 0.5 inches per hour? The response to this
Screening Question must be based on a comprehensive evaluation of
the factors presented in Appendix C.2 and Appendix D.
X
P-3 & P-4
X
P-1, P-2, P-7, P-8
Provide basis:
Based on our test results and utilizing a factor of safety (FOS) of 2.0 for Aardvark testing feasibility and 3.0 for
percolation testing feasibility determination, full infiltration is feasible for P-3 and P-4 only.
Hole #: Infiltration Rate (in/hr): Test Type:
P-1 0.000 Aardvark
P-2 0.000 Aardvark
P-3 1.6 Percolation
P-4 0.6 Percolation
P-7 0.010 Aardvark
P-8 0.037 Aardvark
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc.
2
Can infiltration greater than 0.5 inches per hour be allowed
without increasing risk of geotechnical hazards (slope stability,
groundwater mounding, utilities, or other factors) that cannot be
mitigated to an acceptable level? The response to this Screening
Question must be based on a comprehensive evaluation of the factors
presented in Appendix C.2.
X
Provide basis:
Hole #: Infiltration >0.5 in/hr allowed:
P-1 No, <50 feet from a slope.
P-2 No, <50 feet from a slope.
P-3 No, <50 feet from creek.
P-4 No, <50 feet from creek.
P-7 No, adjacent utility.
P-8 No, adjacent utility.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability.
Appendix C: Geotechnical and Groundwater Investigation Requirements
C-2 July 2018
Worksheet C.4-1 Page 2 of 4
Criteria Screening Question Yes No
3
Can infiltration greater than 0.5 inches per hour be allowed
without increasing risk of groundwater contamination (shallow
water table, storm water pollutants or other factors) that cannot
be mitigated to an acceptable level? The response to this Screening
Question must be based on a comprehensive evaluation of the factors
presented in Appendix C.3.
X
P-7 & P-8
X
P-1, P-2, P-3, P-4
Provide basis:
Hole #: Infiltration >0.5 in/hr allowed:
P-1 No, groundwater <50 feet from existing elevations.
P-2 No, groundwater <50 feet from existing elevations.
P-3 No, groundwater <50 feet from existing elevations.
P-4 No, groundwater <50 feet from existing elevations.
P-7 Yes, groundwater <100 feet from existing elevations.
P-8 Yes, groundwater <100 feet from existing elevations.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability.
4
Can infiltration greater than 0.5 inches per hour be allowed
without causing potential water balance issues such as change of
seasonality of ephemeral streams or increased discharge of
contaminated groundwater to surface waters? The response to this
Screening Question must be based on a comprehensive evaluation of
the factors presented in Appendix C.3.
X
Provide basis:
It is our opinion that infiltration should not cause water balance issues or increased discharge of contaminated
groundwater to surface waters.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability.
Part 1
Result*
If all answers to rows 1 - 4 are “Yes” a full infiltration design is potentially feasible.
The feasibility screening category is Full Infiltration
If any answer from row 1-4 is “No”, infiltration may be possible to some extent but
would not generally be feasible or desirable to achieve a “full infiltration” design.
Proceed to Part 2
No
*To be completed using gathered site information and best professional judgment considering the definition of MEP in
the Regional MS4 Permit. Additional testing and/or studies may be required by City staff to substantiate findings.
Appendix C: Geotechnical and Groundwater Investigation Requirements
C-3 July 2018
Worksheet C.4-1 Page 3 of 4
Part 2 – Partial Infiltration vs. No Infiltration Feasibility Screening Criteria
Would infiltration of water in any appreciable amount be physically feasible without any negative
consequences that cannot be reasonably mitigated?
Criteria Screening Question Yes No
5
Do soil and geologic conditions allow for infiltration in any
appreciable rate or volume? The response to this Screening
Question must be based on a comprehensive evaluation of the factors
presented in Appendix C.2 and Appendix D.
X
P-3 & P-4
X
P-1, P-2, P-7, P-8
Provide basis:
Based on our test results and utilizing a factor of safety (FOS) of 2.0 for Aardvark testing feasibility and 3.0 for
percolation testing feasibility determination, infiltration is feasible for P-3 and P-4 only.
Hole #: Infiltration Rate (in/hr): Test Type:
P-1 0.000 Aardvark
P-2 0.000 Aardvark
P-3 1.6 Percolation
P-4 0.6 Percolation
P-7 0.010 Aardvark
P-8 0.037 Aardvark
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates.
6
Can Infiltration in any appreciable quantity be allowed without
increasing risk of geotechnical hazards (slope stability,
groundwater mounding, utilities, or other factors) that cannot be
mitigated to an acceptable level? The response to this Screening
Question must be based on a comprehensive evaluation of the factors
presented in Appendix C.2.
X
Provide basis:
Hole #: Infiltration >0.5 in/hr allowed:
P-1 No, <50 feet from a slope.
P-2 No, <50 feet from a slope.
P-3 No, <50 feet from creek.
P-4 No, <50 feet from creek.
P-7 No, adjacent utility.
P-8 No, adjacent utility.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates.
Appendix C: Geotechnical and Groundwater Investigation Requirements
C-4 July 2018
Worksheet C.4-1 Page 4 of 4
Criteria Screening Question Yes No
7
Can Infiltration in any appreciable quantity be allowed without
posing significant risk for groundwater related concerns
(shallow water table, storm water pollutants or other factors)?
The response to this Screening Question must be based on a
comprehensive evaluation of the factors presented in Appendix C.3.
X
P-7 & P-8
X
P-1, P-2, P-3, P-4
Provide basis:
Hole #: Infiltration >0.5 in/hr allowed:
P-1 No, groundwater <50 feet from existing elevations.
P-2 No, groundwater <50 feet from existing elevations.
P-3 No, groundwater <50 feet from existing elevations.
P-4 No, groundwater <50 feet from existing elevations.
P-7 Yes, groundwater <100 feet from existing elevations.
P-8 Yes, groundwater <100 feet from existing elevations.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates.
8
Can infiltration be allowed without violating downstream water
rights? The response to this Screening Question must be based on a
comprehensive evaluation of the factors presented in Appendix C.3.
X
Provide basis:
Researching downstream water rights and evaluating water balance issues to stream flows is beyond the
scope of the geotechnical engineer. However, it is our opinion that infiltration should not impact downstream
water rights.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates.
Part 2
Result*
If all answers from row 5-8 are yes then partial infiltration design is potentially
feasible. The feasibility screening category is Partial Infiltration.
If any answer from row 5-8 is no, then infiltration of any volume is considered to be
infeasible within the drainage area. The feasibility screening category is No Infiltration.
No Infiltration
*To be completed using gathered site information and best professional judgment considering the definition of MEP in
the Regional MS4 Permit. Additional testing and/or studies may be required by Agency/Jurisdictions to substantiate
findings.
41571 Corning Place, Suite 101 ■ Murrieta, California 92562 ■ Telephone 951.304.2300 ■ www.geoconinc.com
Project No. T2754-22-04A
July 20, 2023
REVISED July 24, 2023
Mr. Clint Gulick
TRT Holdings, Inc.
4001 Maple Avenue, Suite 600
Dallas, Texas 75219
Subject: SUITABILITY OF RIGID PAVEMENT FOR
VACUUM TRUCK LOADING
CHAMPIONS COURSE RENOVATIONS
2100 COSTA DEL MAR ROAD
CARLSBAD, CALIFORNIA
References: 1) O’Day Consultants, 2023, Grading Plan for: Omni Resort Golf Course, Street
Sections, Details, Abandonment Notes, GR 2023-0018, Project No. CUP2023-0001,
Drawing No. 539-4C, Sheet 3 of 12, dated month of January.
2) Geocon West, Inc., 2021, Limited Geotechnical Investigation, Champions Course
Renovations, Omni La Costa Resort & Spa, 2100 Costa Del Mar Road, Carlsbad,
California, Project No. T2754-22-04, dated April 15, 2021.
Mr. Gulick:
Geocon West, Inc. (Geocon) has been requested by O’Day Consultants (O’Day) to evaluate the
suitability of the proposed rigid concrete golf cart path to support vacuum truck loading, based on
comments provided by Leucadia Water District. Sheet 3 (Drawing No. 539-4C) of the grading plans
(Reference No. 1) provides the proposed golf cart path detail, depicting the golf cart path to have a
minimum rigid concrete pavement section of 4 inches, overlying 12 inches of compacted subgrade.
This suitability letter is associated with our Limited Geotechnical Investigation (Reference No. 2),
which provides an R-value of 7 for use in our evaluation herein.
Based on information provided to us by O’Day via email correspondence, we understand that the golf
cart paths may be subjected to estimated vacuum truck loading of up to 54,500 pounds, distributed over
two single-axles, during its design life. We have assumed that the front axle will support approximately
30% of the weight of the vehicle while the rear axle will support approximately 70% of the weight. If
an alternate weight distribution is appropriate, they should be provided to Geocon for review and
update of the recommendations as necessary.
Given the resulting axle weights, the vacuum trucks are anticipated to impose an Equivalent Single
Axle Load (ESAL) of 17.823 per pass. Based on information provided to us by O’Day, the vacuum
trucks are expected to visit the site at a frequency of once per month, which we assume will be over a
20-year pavement design life. Based on this frequency, the vacuum trucks would accumulate 4,278
GEOCON
W E S T, I N C.
GEOTECHNI CA L ■ ENVIRONMENTAL ■ MATERIA L S °'
Geocon Project No. T2754-22-04A - 2 - July 20, 2023
REVISED July 24, 2023
ESAL’s. As a result of the ESAL being less than the minimum 5,000 ESAL value needed to use Table
613.3C of the Caltrans Highway Design Manual, we selected an ESAL of 5,000, which correlates to a
Traffic Index (TI) value of 5.0.
We evaluated the suitability of the 4-inch rigid concrete pavement section proposed in design of the
golf cart path, which was performed using the AASHTO concrete pavement design method, which
resulted in the proposed 4-inch rigid concrete pavement section being suitable to support the
anticipated vacuum truck loading, based on the conditions discussed herein.
An aggregate base roadway can be constructed for vacuum truck access. The aggregate base section
should be a minimum thickness of 16½ inches overlying compacted subgrade. The aggregate base
section and soil subgrade should both be compacted to a minimum of 95% relative compaction in
accordance with ASTM D1557. Aggregate base materials should conform to Section 26 of the Caltrans
Standard Specifications (latest edition).
If you have any questions regarding this correspondence, or if we may be of further service, please
contact the undersigned at your convenience.
Very truly yours,
GEOCON WEST, INC.
Andrew T. Shoashekan
PE 93940
Lisa A. Battiato
CEG 2316
ATS:LAB
Distribution: Addressee (clint.gulick@omnihotels.com)
Keith Hansen (Keithh@odayconsultants.com)
Attachments: LIMITATIONS AND UNIFORMITY OF CONDITIONS
Geocon Project No. T2754-22-04A - 3 - July 20, 2023
REVISED July 24, 2023
LIMITATIONS AND UNIFORMITY OF CONDITIONS
The recommendations of this letter pertain only to the site investigated and are based upon the
assumption that the soil conditions do not deviate from those disclosed in the referenced geotechnical
investigation (Reference No. 2). If any variations or undesirable conditions are encountered during
construction, or if the proposed construction will differ from that anticipated in the referenced report,
Geocon should be notified so that supplemental recommendations can be given. The evaluation or
identification of the potential presence of hazardous or corrosive materials was not part of the scope of
services provided by Geocon.
This letter is issued with the understanding that it is the responsibility of the owner or 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 that the
necessary steps are taken to see that the contractor and subcontractors carry out such recommendations
in the field.
The recommendations of this letter are valid as of the date of this letter. However, changes in the
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 recommendations of this letter may be invalidated wholly or partially by changes
outside our control. Therefore, this letter is subject to review and should not be relied upon after a
period of one year.
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 presented 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.