Lake Forest City Council
March 17, 2026

980
Table C-5. Operational Emergency Generator Criteria Air Pollutant Emissions Factors Costco Foothill RanchLake Forest, California
E
qui
pment Typ
e
TOG1,2
(g/bh
p-hr)
ROG1,2,3
(g/bh
p-hr)
NOX
1 (g/bh
p-hr)
CO1
(g/bh
p-hr)
SO2
4 (g/bh
p-hr)
PM10
4 (g/bh
p-hr)
PM2.5
4 (g/bh
p-hr)
Emergency Generator - CNG (0-500 HP) 0.01 4.00E-05 0.10 0.94 0.002 0.03 0.03 Abbreviations:
bhp-hr - brake horsepower- hour PM2.5 - particulate matter less than 2.5 microns in diameter CalEEMod
® - California Emissions Estimator Model ROG - reactive organic gases CNG - compressed natural gas SO2 - sulfur dioxide
CO - carbon monoxide THC - total hydrocarbonsg - gram TOG - total organic gasesHP - horsepower USEPA - United States Environmental Protection AgencyNOx - nitrogen oxide compounds (NO + NO2) VOC - volatile organic compound PM10 - particulate matter less than 10 microns in diameter Notes:
1 The emergency generator will have a catalytic converter installed to meet lower NOX, THC (TOG and ROG), and CO emission factors. These controlled emission factors are based on certified test data from Project-specific information. 2 The THC emission factor was converted to TOG and VOC emission factors per the USEPA Conversion Factors for Hydrocarbon Emission Components.

Available at: https://19january2017snapshot.epa.gov/www3/otaq/models/nonrdmdl/nonrdmdl2005/420r05015.pdf. Accessed: October 2025. 3 For purposes of this analysis VOC emissions are assumed to be equal to ROG.4 Based on CalEEMod ® defaults.

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Costco Wholesale Project
CEQA Guidelines 15183 | Environmental Compliance Checklist Appendix B
Appendix B – Cultural Resources Report
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KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701

MEMORANDUM
TO:

FROM:

DATE:

SUBJECT:

Mr. Michael Okuma, AVP Real Estate Development, Costco Wholesale Corporation Megan T. Hawkins, M.A., RPA
January 6, 2026
Foothill Ranch Preliminary Cultural Resource Desktop Review, Orange County, California Kleinfelder, Inc. (Kleinfelder) conducted a desktop cultural resource review of the proposed location of a Costco Wholesale warehouse located in the Foothill Ranch Planned Community of the City of Lake Forest, Orange County, California (study area; Attachment A). This desktop review was conducted at the request of Costco as part of its due diligence and includes a records search at the California Historical Resources Information System (CHRIS) South Central Coastal Information Center (SCCIC), a review of historical maps and aerial imagery, and a request to the Native American Heritage Commission for a Sacred Lands File search. A field survey was not conducted as part of this review.

As a result of the desktop review, one previously recorded cultural resource is identified within the study area and 23 cultural resources are identified within a 0.5-mile radius of the study area. Seven previously conducted cultural resources studies intersect the study area, and 19 previously conducted cultural resources studies are identified within the 0.5-mile radius search buffer. A review of historical maps and aerial imagery indicates that the area within and near the study area is undeveloped with trails and/or informal roads and was not visibly altered until 1992 when an ephemeral parking lot structure was developed. The study area was cleared and graded in 1994, and the current building and parking lot were constructed by 1999.

Due to the presence of precontact, isolated surface artifacts within the study area and precontact sites in the vicinity of the study area, there is high sensitivity for precontact resources to occur within the Project area. Preconstruction subsurface survey and/or testing is not feasible as the study area is developed with a commercial building and associated parking lot. Based on this background review, Kleinfelder recommends archaeological awareness training for Project personnel conducting ground disturbing activities prior to the start of work. If construction or grading activities result in the discovery of significant historic or prehistoric archaeological artifacts or unique paleontological resources, all work within 100 feet of the discovery shall cease, the Director of Community Development shall be notified, the resources shall be examined by a qualified archaeologist, paleontologist, or historian for appropriate protection and preservation measures; and work may only resume when appropriate protections are in place and have been approved by the Community Development Director. If human remains are discovered during any ground disturbing activity, work shall stop until the Director of Community Development and the Orange County Coroner have been contacted. If the human remains are determined to be of Native American origin, the Native American Heritage Commission and the most likely descendants shall be consulted; and work may only resume when appropriate measures have been taken and approved by the Community Development Director. The approving regulatory agency should be contacted, and a qualified professional archaeologist retained to analyze the significance of the find and formulate further mitigation (e.g., Item: 11
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KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701 Project relocation, excavation plan, and protective cover) in consultation with culturally affiliated tribes or other descendant groups, where applicable.

Should further technical studies be required by the local jurisdiction to comply with California Environmental Quality Act (CEQA) and/or with Section 106 of the National Historic Preservation Act (NHPA), as applicable. Additional effort may include evaluation of any resources within the study area for inclusion in the California Register of Historical Resources (CRHR) and/or the National Register of Historic Places (NRHP).

Project Location and Understanding
The study area is located at 26602 Towne Centre Drive, between State Route 241 and Portola Parkway, in Foothill Ranch, California. It is currently developed with a vacant commercial building and associated parking lots and driveways. The study area consists of 16.28 acres of developed land within Assessor’s Parcel Number (APN) 612-093-13. The study area boundary and 0.5-mile radius search buffer are found on the U.S. Geological Survey El Toro (1982), 7.5-minute quadrangles, in Township 06 South, Range 08 West, Section 1, San Bernadino Base Meridian (SBBM). Kleinfelder understands that the study area is currently occupied by a former movie theatre and parking lot, and that Costco plans to construct a new warehouse on the proposed location.

CHRIS Records Search
On December 5, 2025, a records search of the study area and a 0.5-mile buffer around the study area was conducted at the SCCIC at California State University, Fullerton (I.C. File number 27545.13625). The purpose of the records search was to identify any prehistoric and/or historic-period cultural resources and studies that have been previously documented in the study area to better understand the archaeological sensitivity of the area.

The SCCIC records search identified one previously recorded cultural resource within the study area and 23 cultural resources within a 0.5-mile radius of the study area (Table 1 and Table 2; Attachment B). Seven previous studies intersect the study area, and 19 previous cultural studies intersect the 0.5-mile radius search buffer (Table 3 and Table 4; Attachment B).

Table 1. Previously recorded resources within the Study Area.

Primary No. Trinomial Age Type Description
P-30-100280 Not Indicated Prehistoric Isolates
Prehissotricc isolotes that include a mano,
milling stone, core tool, flake tool, and
hammerstone
Table 2. Previously recorded resources within 0.5-mile of the Study Area.

Primary No. Trinomial Age Type Description
P-36-000420 CA-SBR-000420 Prehistoric Site Lithic scatter, bedrock milling feature, and habitation debris
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KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701 Table 2. Previously recorded resources within 0.5-mile of the Study Area.

Primary No. Trinomial Age Type Description
P-36-002328 CA-SBR-002328 Prehistoric Site Lithic scatter, hearths/pits, and quarry P-36-002330 CA-SBR-002330H Historic Site Lavic Chinese Labor Camp P-36-002331 CA-SBR-002331 Prehistoric Site Lithic scatter P-36-002910 CA-SBR-002910H Historic Structure/Site
National Old Trails Highway Historic Route
66 is an engineering structure with
roads/trails/railroad grades, a bridge,
culvert, retaining wall, and
privies/dumps/trash scatters
P-36-003593 CA-SBR-003593 Prehistoric Site Pisgah Crater Lithic scatter P-36-004161 CA-SBR-004161H Historic Site Privies/dumps/trash scatters P-36-004401 CA-SBR-004401 Not
Indicated Not Indicated Not indicated
P-36-004404 CA-SBR-004404H Historic Site Pisgah Historic Site #5 consists of privies/dumps/trash scatters
P-36-004547 CA-SBR-004547 Historic Site Pisgah Site #2 consists of geofeatures P-36-005441 CA-SBR-005441
Prehistoric,
Historic,
Unknown
Site Pisgah-1 consists of cairns/rock features
P-36-005442 CA-SBR-005442 Prehistoric Site Pisgah-2 consists of a rock shelter/cave P-36-006693 CA-SBR-006693H Historic Structure/Site
Atchison, Topeka & Santa Fe Railroad
consists of a railroad, train, bridge,
roads/trails/railroad grades, and
privies/dumps/trash scatters
P-36-007179 CA-SBR-007179H Historic Site Pisgah Historic Site # 1 consists of privies/dumps/trash scatters
P-36-007180 CA-SBR-007180H Historic Site Pisgah Historic Site # 2 consists of privies/dumps/trash scatters
P-36-007941 CA-SBR-007941 Prehistoric Site Cairns/rock features P-36-020271 Not Indicated Historic Structure
Lavic Lake / Kenton Mill Road resource
consists of roads/trails/railroad grades,
and a highway/trail
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KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701 Table 2. Previously recorded resources within 0.5-mile of the Study Area.

Primary No. Trinomial Age Type Description
P-36-024509 Not Indicated Historic Site Privies/dumps/trash scatters P-36-026491 Not Indicated Historic Site Roads/trails/railroad grades P-36-026492 Not Indicated Historic Site Roads/trails/railroad grades P-36-026494 Not Indicated Historic Structure Roads/trails/railroad grades P-36-032177 Not Indicated Historic Other Privies/dumps/trash scatters P-36-061070 Not Indicated Prehistoric Other Pisgah Site 14 Table 3. Previously conducted studies within the Study Area.

Report No. Date Author Title
OR-00571 1973 Ahlering, Michael L.

Report of Findings of a Scientific Resources Survey and Study: Conducted on a Portion of the Whiting Ranch,
Orange County, California
OR-00591 1980 Cooley, Theodore G. and
Cottrell, Marie G. Archaeological Assessment of the Whiting Ranch OR-00648 1982 Breece, Bill and Padon,
Beth
Cultural Resource Survey: Archaeological Resources:

Foothill Transportation Corridor, Phase II
OR-00899 1987 Not Indicated
Draft Environmental Impact Report No. 481 Foothill
Ranch (formerly Whiting Ranch) Planned Community
Area Plan, General Plan Amendment and Zone Change
OR-01354 1980 Munoz, Jeanne History and Historical Resources of the Whiting Ranch OR-01364 1993 Brock, James P. Report on Archaeological Monitoring of Rough Grading of Planning Area 6, Foothill Ranch, El Toro, California OR-01467 1992 Not Indicated
Final Report on Archaeological Investigations for Tracts 11725 and 13419: Phase 1 the Foothill Ranch
Development Orange County, California
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KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701 Table 4. Previous studies conducted within 0.5-mile of the Study Area Report No. Date Author Title
OR-00611 1988 Bissell, Ronald M. Cultural Resources Reconnaissance of the Baker Ranch Property, El Toro, Orange County
OR-00629 1981 Cottrell, Marie G. Archaeological Resource Assessment for Two Parcels Near El Toro, California
OR-00934 1982 Drover, Christopher E.
and Henry C. Koerper
Archaeological Test Investigations: The Phase I
Development of the Whiting Ranch
OR-00970 1989 Brock, James P.

Report on Archaeological Monitoring of Rough Grading
for the Baker Extension of Lake Forest Drive, El Toro,
California
OR-01088 1990 Brock, James P.

Report on Archaeological Monitoring of Rough Grading
of Bake Parkway from Portola Parkway to Station
159+40.81, El Toro, California
OR-01308 1992 Macko, Michael E. and
Hurd, Gary S.

Final Report Buried Archaeological Features in Borrego
Canyon Results of Archaeological Monitoring and Data
Recovery Excavations for the Foothill Transportation
Corridor, Northern Segment, Construction Sections F8
and F9
OR-01309 1993 Macko, Michael E.

Final Report Summary of Archaeological Monitoring,
Test Excavations, and Data Recovery for the Foothill
Transportation Corridor Northern Segment
OR-01310 1992 Macko, Michael E. and
Hurd, Gary S.

Results of Archaeological Test Excavations for the
Foothill Transportation Corridor Northern Segment,
Construction Section F8 and F9
OR-01349 1993 Brock, James
Report on Archaeological Monitoring of Rough Grading
of Planning Areas 3 and 4, Foothill Ranch, El Toro,
California
OR-01376 1994 Brock, James P. Archaeology of Foothill Ranch Planning Area 15 and a Portion of Planning Area 16, El Toro, California
OR-01495 1996 Brock, James P. Report on Archaeological Monitoring of Rough Grading of Planning Area 8, Foothill Ranch, El Toro, California OR-01687 1998 Brock, James P.

Report on Archaeological Monitoring of Rough Grading
of Planning Area 16, Tentative Tract 13419, Foothill
Ranch, El Toro, California
OR-01947 1998 Duke, Curt
Cultural Resource Assessment for the Los Angeles
Cellular Telephone Company, Facility Number E875,
Located at 26736 Portola Parkway, County of Orange,
California
OR-02334 2001 Hoover, Anna M.

Archaeological and Paleontological Monitoring at Lots 9 and 10, Tract 15753, Lake Forest, Orange County,
California
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KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701 Table 4. Previous studies conducted within 0.5-mile of the Study Area Report No. Date Author Title
OR-02928 1994 Demcak, Carol R.

Final Report of Salvage Level Investigations at ORA-758, Alton Parkway Extension Project, County of Orange,
California
OR-03052 2004 Harper, Caprice D. Cultural Resource Assessment Cingular Wireless Facility No. Sc 174-01 Foothill Ranch, Orange County, California OR-03748 2009 Maxon, Patrick O. Phase II Archaeological Evaluation CA-ORA-1004 & CAORA-1150 OR-03749 2008 Maxon, Patrick O.

Phase I Cultural Resources Reconnaissance SurveyProposed Alton Parkway Extension Project, Including Baker Ranch, Lake Forest, CA
OR-04336 2012 O'Neil, Stephen and
Black, Megan
Identification and Evaluation of Historic Properties ADA Wheelchair Access Ramp Improvement Project, City of
Lake Forest Orange County, California
Historical Map Review
Kleinfelder reviewed historical maps depicting features such as towns, structures, roads, railroads, and other cultural features to provide information regarding the potential for the presence of historic-period cultural resources within and near the study area. Historical maps are available at websites, in particular the U.S. Geological Survey (USGS) topoView site and the U.S. Department of the Interior Bureau of Land Management (BLM) General Land Office (GLO) Records site. In addition, historical aerial imagery from 1946 through 1999 was reviewed online at the Nationwide Environmental Title Research (NETR) website.

Kleinfelder reviewed the following historical sources:
• 1873 GLO for Township 06S, Range 08W, Section 1, SBBM • 1902 USGS Corona 125,000 topographic quadrangle
• 1942 USGS Santiago Peak 62,500 topographic quadrangle [edited 1960] • 1950 USGS El Toro 24,000 topographic quadrangle
• 1968 USGS El Toro 24,000 topographic quadrangle [edited 1970] • 1974 USGS El Toro 24,000 topographic quadrangle [edited 1975] • 1997 USGS El Toro 24,000 topographic quadrangle [edited 2000] • 1946, 1952, 1967, 1972, 1980, 1992, 1994, and 1999 NETR Historical Aerials The following summarizes the results of the historical map review for the study area and its vicinity:
• The 1873 GLO survey plat for Township 06S, Range 08W, Section 8 is located within Lot No. 38, part of Rancho Canada de los Alisos. There are no historic-era resources or evidence of historic land utilization within map Section 1 (BLM 2025).
• The 1902 Corona quadrangle shows no historic-era resources within the study area; however, there is a trail or informal road approximately 800 feet northwest of it. The trail connects to a formal road approximately 1.4 miles southwest of the study area, and it terminates about 0.5 mile Item: 11
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KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701 northeast of the study area. There are no structures or other historic features depicted (USGS 2025a).
• The 1942 Santiago Peak quadrangle shows no historic-era resources within the study area. The informal road is no longer depicted, nor is the formal road that it converged with. There is another trail or informal road that traverses in an east-west direction, approximately 380 feet north of the study area. This informal road connects to a network of informal roads to the east and terminates west of the study area (USGS 2025b).
• The 1950 El Toro quadrangle depicts no historic-era resources within the study area. The informal road previously depicted is approximately 520 feet north of the study area, and it connects to other informal roads and/or trails within the vicinity. No new development is noted in the area (USGS 2025c).
• The 1968 El toro quadrangle shows a trail or informal road traversing through the southeast corner of the study area in an east-west direction. There is an informal road approximately 470 feet north of the study area and another informal road 360 feet south of the study area. Other than informal roads, there are no structures or other indications of development depicted within or near the study area (USGS 2025d).
• The 1974 El Toro quadrangle depicts the informal road in the southeast corner of the study area.

There is an informal road approximately 400 feet north and another 230 feet south of the study area. Aside from agricultural fields depicted south of the study area, there are no structures or indications of development within and near the study area (USGS 2025e). • The 1997 El Toro quadrangle depicts development within the vicinity of the study area but not directly within the study area. A highway, State Route 241, runs parallel to the southeast boundary, and several large structures are present just outside the study area. One structure is approximately 400 feet southeast, two structures are approximately 250 feet east, and another structure is approximately 85 feet north. There are roads associated with these structures located east and northwest of the study area (USGS 2025f).
• Historical aerial imagery from 1946 shows no development within or near the study area, including no trails or roads. The area consists of shrubs and/or grasses, and there are agricultural fields, likely orchards, to the south (NETR 2025a).
• Historical aerial imagery from 1952 shows no development within the study area. It consists primarily of shrubs and/or grasses with some trees in the south corner. There are trails or informal roads to the north, but no structures are visible within or near the study area (NETR 2025b). • Historical aerial imagery from 1967 shows an informal road in the southeast corner of the study area. There is a well-traveled road to the south and another informal road to the north. In addition to the orchards, more of the land to the south is utilized for agriculture. There are no structures or buildings within or near the study area (NETR 2025c). • Historical aerial imagery from 1972 showsthe road within the study and the road to the north has been surfaced. There are a few trails and/or informal roads visible within the area. The land to the south is almost completely utilized for agriculture, primarily what appears to be orchards (NETR 2025d).

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KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701 • Historical aerial imagery from 1980 shows the area as mostly unchanged, and there are no structures or buildings within the study area. There is some development within the farmland to the south, including what appear to be two large cylindrical tanks (NETR 2025e). • Historical aerial imagery from 1992 shows a parking lot intersecting and encompassing much of the study area. A formal, paved road extends from a main road to the north, likely Portola Parkway, to the parking area. There are several roads still present within the vicinity, and new development is evident to the east of the parking lot (NETR 2025f). • Historical aerial imagery from 1994 shows that the study area has been completely cleared and graded, and the parking lot is no longer present. The south and northwest sides of the study area are bounded by a state route and a paved road. There is another paved road a few hundred feet northeast, and the area to the northwest is in the process of being developed. There is a long parking lot, a small structure, and cleared rectangular areas directly northwest (NETR 2025g). • Historical aerial imagery from 1999 shows the current parking structure present within the study area. In addition, the present-day building configuration within the vicinity of the study area is visible (NETR 2025h).

Sacred Lands File Search
Kleinfelder contacted the Native American Heritage Commission (NAHC) and made a Sacred Lands File (SLF) search request to identify whether sacred lands or Tribal cultural resources are located within the study area and to obtain a list of Tribes affiliated with the region who may be able to provide additional information regarding any areas of Tribal concern.

On December 3, 2025, the NAHC cultural resources analyst contacted Kleinfelder and indicated that the results of the SLF search were negative for the Site (Attachment C). The NAHC response also included a list of Native American Tribes who may also have knowledge of cultural resources in the study area.

Summary
The proposed location of a Costco Wholesale warehouse is in a commercial area and encompasses a vacant commercial building and parking lot. An SCCIC review of previously recorded cultural resources identified one previously recorded cultural resource within the study area and 24 cultural resources within its 0.5-mile radius. Seven previous studies intersect the study area, and 19 previous cultural studies intersect the 0.5-mile radius of the study area. A review of historical maps and aerial imagery indicates that the area within and near the study area was undeveloped with a trail and/or informal road until approximately 1992, and the current structure and parking lot was constructed between 1994 and 1999.

Due to the presence of precontact, isolated surface artifacts within the study area and precontact sites in the vicinity of the study area, there is high sensitivity for precontact resources to occur within the Project area. Preconstruction subsurface survey and/or testing is not feasible as the study area is developed with a commercial building and associated parking lot. Based on this background review, Kleinfelder recommends archaeological awareness training for Project personnel conducting ground disturbing activities prior to the start of work. If construction or grading activities result in the discovery of significant historic or prehistoric archaeological artifacts or unique paleontological resources, all work within 100 feet of the discovery shall cease, the Director of Community Development shall be notified, the resources Item: 11
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KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701 shall be examined by a qualified archaeologist, paleontologist, or historian for appropriate protection and preservation measures; and work may only resume when appropriate protections are in place and have been approved by the Community Development Director. If human remains are discovered during any ground disturbing activity, work shall stop until the Director of Community Development and the Orange County Coroner have been contacted. If the human remains are determined to be of Native American origin, the Native American Heritage Commission and the most likely descendants shall be consulted; and work may only resume when appropriate measures have been taken and approved by the Community Development Director. The approving regulatory agency should be contacted, and a qualified professional archaeologist retained to analyze the significance of the find and formulate further mitigation (e.g., Project relocation, excavation plan, and protective cover) in consultation with culturally affiliated tribes or other descendant groups, where applicable.

Should further technical studies be required by the local jurisdiction to comply with CEQA and/or with Section 106 of the NHPA, as applicable. Additional effort may include evaluation of any resources within the study area for inclusion in the CRHR and/or the NRHP.

Sincerely,

KLEINFELDER
Megan T. Hawkins, M.A., RPA
Senior Archaeologist
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KLEINFELDER 3130 Kilgore Road, Suite 200, Rancho Cordova, CA 95670 p | 916.366-1701 References Cited
Bureau of Land Management (BLM)
2025 DM ID: 291024 from 1873. Accessed December 9, 2025, from:
https://glorecords.blm.gov/details/survey/default.aspx?dm_id=291025&sid=3rx5dkzw.ukb&surv eyDetailsTabIndex=1.

Nationwide Environmental Title Research (NETR)
2025a 1946 Historic Aerials. Accessed December 8, 2025, from: http://historicaerials.com/viewer. 2025b 1952 Historic Aerials. Accessed December 8, 2025, from: http://historicaerials.com/viewer. 2025c 1967 Historic Aerials. Accessed December 8, 2025, from: http://historicaerials.com/viewer. 2025d 1972 Historic Aerials. Accessed December 8, 2025, from: http://historicaerials.com/viewer. 2025e 1980 Historic Aerials. Accessed December 8, 2025, from: http://historicaerials.com/viewer. 2025f 1992 Historic Aerials. Accessed December 9, 2025, from: http://historicaerials.com/viewer. 2025g 1994 Historic Aerials. Accessed December 9, 2025, from: http://historicaerials.com/viewer. 2025h 1999 Historic Aerials. Accessed December 9, 2025, from: http://historicaerials.com/viewer.

United States Geological Survey (USGS)
2025a 1902/1911 Corona 30-Minute topographic map. Accessed December 8, 2025, from:
https://ngmdb.usgs.gov/ht-bin/tv_browse.pl?id=275cbbddfd2108b59805c685e8b57e5a. 2025b 1942 Santiago Peak 15-Minute topographic map. Accessed December 8, 2025, from:
https://ngmdb.usgs.gov/ht-bin/tv_browse.pl?id=bb38507bd8c0f0fe3978743243642f62. 2025c 1950 El Toro 7.5-Minute topographic map. Accessed December 8, 2025, from:
https://ngmdb.usgs.gov/ht-bin/tv_browse.pl?id=6a7d77b29e2bfd68cb7a7e18dbbddf5f. 2025d 1968/1970 El Toro 7.5-Minute topographic map. Accessed December 8, 2025, from:
https://ngmdb.usgs.gov/ht-bin/tv_browse.pl?id=4cdc95417659c8f15b6a3920049d706c. 2025e 1974/1975 El Toro 7.5-Minute topographic map. Accessed December 9, 2025, from:
https://ngmdb.usgs.gov/ht-bin/tv_browse.pl?id=dd8ec9e18bdb3e49279a6b7311386d83. 2025f 1997/2000 El Toro 7.5-Minute topographic map. Accessed December 9, 2025, from:
https://ngmdb.usgs.gov/ht-bin/tv_browse.pl?id=26360a0e24eb7b2cbf2bf5e2d50938d0.

Attachments:

Attachment A – Study Area Topographic Map
Attachment B – South Central Coastal Information Center Records Search Results Attachment C – Native American Heritage Commission Records Search Results Item: 11
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Attachment A: Study Area Topographic Map
Item: 11
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Project
Location ^_
Copyright:© 2013 National Geographic Society, i-cubed
±
0 300 600
Meters
Record Search
Foothill Ranch
Orange County, California
USGS 7.5' Quad: EL TORO (1982)
Legal Description: T06S, R08W SEC 1
0 1,000 2,000
Feet
Created By: dlmoore Document Path: G:\Costco\Costco_FoothillRanch\_ARCPRO_PROJECT\Costco_FoothillRanch.aprx 1 inch = 2,000 feet
Scale 1:24,000
Legend
Half-mile Search Radius
Project Area
Item: 11
994
Attachment B: South Central Coastal Information Center Records Search Results Item: 11
995
South Central Coastal Information Center
California State University, Fullerton
Department of Anthropology MH-426
800 North State College Boulevard
Fullerton, CA 92834-6846
657.278.5395 / FAX 657.278.5542
[email protected]
California Historical Resources Information System
Orange, Los Angeles, and Ventura Counties
_____________________________________________________________________________ 12/5/2025 Records Search File No.: 27545.13625

Megan Hawkins
Kleinfelder
770 First Avenue, Suite 400
San Diego, CA 92101
Re: Records Search Results for the Foothill Ranch Desktop Review The South Central Coastal Information Center received your records search request for the project area referenced above, located on the El Toro, CA USGS 7.5’ quadrangle. The following reflects the results of the records search for the project area and a ½-mile radius:

As indicated on the data request form, the locations of resources and reports are provided in the following format: ☐ custom GIS maps ☒ shape files ☐ hand-drawn maps Resources within project area: 1 30-100280
Resources within ½-mile radius: 24 SEE ATTACHED LIST
Reports within project area: 7 OR-571, OR-591, OR-648, OR-899, OR-1354, OR-1364, OR-1467 Reports within ½-mile radius: 19 SEE ATTACHED LIST
Resource Database Printout (list): ☒ enclosed ☐ not requested ☐ nothing listed Resource Database Printout (details): ☒ enclosed ☐ not requested ☐ nothing listed Resource Digital Database (spreadsheet): ☒ enclosed ☐ not requested ☐ nothing listed Report Database Printout (list): ☒ enclosed ☐ not requested ☐ nothing listed Report Database Printout (details): ☒ enclosed ☐ not requested ☐ nothing listed Report Digital Database (spreadsheet): ☒ enclosed ☐ not requested ☐ nothing listed Resource Record Copies: ☒ enclosed ☐ not requested ☐ nothing listed Report Copies: ☒ enclosed ☐ not requested ☐ nothing listed OHP Built Environment Resources Directory (BERD) 2022: ☒ available online; please go to https://ohp.parks.ca.gov/?page_id=30338
Archaeo Determinations of Eligibility 2022: ☒ enclosed ☐ not requested ☐ nothing listed Los Angeles Historic-Cultural Monuments ☐ enclosed ☒ not requested ☐ nothing listed Historical Maps: ☐ enclosed ☒ not requested ☐ nothing listed San Bernardino Historical Maps: ☒ not available at SCCIC; please go to https://ngmdb.usgs.gov/topoview/viewer/#4/39.98/-100.02 Ethnographic Information: ☒ not available at SCCIC
Item: 11
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Historical Literature: ☒ not available at SCCIC
GLO and/or Rancho Plat Maps: ☒ not available at SCCIC
Caltrans Bridge Survey: ☒ not available at SCCIC; please go to http://www.dot.ca.gov/hq/structur/strmaint/historic.htm Shipwreck Inventory: ☒ not available at SCCIC; please go to http://shipwrecks.slc.ca.gov/ShipwrecksDatabase/Shipwrecks_Database.asp Soil Survey Maps: (see below) ☒ not available at SCCIC; please go to http://websoilsurvey.nrcs.usda.gov/app/WebSoilSurvey.aspx Please forward a copy of any resulting reports from this project to the office as soon as possible. Due to the sensitive nature of archaeological site location data, we ask that you do not include resource location maps and resource location descriptions in your report if the report is for public distribution. If you have any questions regarding the results presented herein, please contact the office at the phone number listed above.

The provision of CHRIS Data via this records search response does not in any way constitute public disclosure of records otherwise exempt from disclosure under the California Public Records Act or any other law, including, but not limited to, records related to archeological site information maintained by or on behalf of, or in the possession of, the State of California, Department of Parks and Recreation, State Historic Preservation Officer, Office of Historic Preservation, or the State Historical Resources Commission.

Due to processing delays and other factors, not all of the historical resource reports and resource records that have been submitted to the Office of Historic Preservation are available via this records search. Additional information may be available through the federal, state, and local agencies that produced or paid for historical resource management work in the search area. Additionally, Native American tribes have historical resource information not in the CHRIS Inventory, and you should contact the California Native American Heritage Commission for information on local/regional tribal contacts.

Should you require any additional information for the above referenced project, reference the record search number listed above when making inquiries. Requests made after initial invoicing will result in the preparation of a separate invoice.

Thank you for using the California Historical Resources Information System, Michelle Galaz Cornforth
Assistant Coordinator
Enclosures:
(X) GIS Shapefiles – 51 shapes
(X) Resource Database Printout (list) – 5 pages
(X) Resource Database Printout (details) – 37 pages
Item: 11
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(X) Resource Digital Database (spreadsheet) – 25 lines
(X) Report Database Printout (list) – 4 pages
(X) Report Database Printout (details) – 30 pages
(X) Report Digital Database (spreadsheet) – 26 lines
(X) Resource Record Copies – (within project area) - 262 pages (X) Report Copies – (within project area) – 2 pages
(X) Archaeological Determinations of Eligibility (2022) – 6 lines (X) National Register Status Codes – 1 pages
(X) Invoice #27545.13625
Item: 11
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Attachment C: Native American Heritage Commission Records Search Results Item: 11
999
STATE OF CALIFORNIA Gavin Newsom, Governor

NATIVE AMERICAN HERITAGE COMMISSION

November 14, 2025
Megan Hawkins
Kleinfelder
Via Email to: [email protected]
Re: Foothill Ranch Desktop Review Project, Orange County To Whom It May Concern:

As requested, a search of the Native American Heritage Commission (NAHC) Sacred Lands File (SLF) was completed based on information submitted for the above referenced project. The results were negative. Be aware that tribes do not always record their sacred sites in the SLF, nor are they required to do so. As such, an SLF search is not a substitute for consultation with all tribes that are traditionally and culturally affiliated with a project’s geographic area.

Attached is a list of Native American tribes that are traditionally and culturally affiliated with the project’s geographic area. Please contact all of the listed tribes as they may have information about sacred sites within the project area that is not listed with the NAHC.

If within two weeks of notification, a response has not been received, the Commission requests that you follow up with a telephone call or email to ensure that the project information was received.

If you receive notification of a change of address or phone number from a tribe, please inform the NAHC so that we can assure that our lists contain current information.

In addition to engaging in tribal consultation, you should consult the appropriate regional California Historical Research Information System (CHRIS) information center to determine whether it has information regarding the presence of recorded archaeological sites within the project area.

If you have any questions or need additional information, please contact me at [email protected].

Sincerely,
Andrew Green
Cultural Resources Analyst
Attachment

CHAIRPERSON
Reginald Pagaling
Chumash

VICE-CHAIRPERSON
Buffy McQuillen
Yokayo Pomo, Yuki,
Nomlaki

SECRETARY
Isaac Bojorquez
Ohlone-Costanoan

PARLIAMENTARIAN
Wayne Nelson
Luiseño

COMMISSIONER
Sara Dutschke
Miwok

COMMISSIONER
Stanley Rodriguez
Kumeyaay

COMMISSIONER
Bennae Calac
Pauma-Yuima Band of
Luiseño Indians

COMMISSIONER
Vacant

COMMISSIONER
Vacant

ACTING EXECUTIVE

SECRETARY
Michelle Carr

NAHC HEADQUARTERS
1550 Harbor Boulevard
Suite 100
West Sacramento,
California 95691
(916) 373-3710
[email protected]
Item: 11
1000
Tribe Name Fed (F)
Non-Fed (N)
Contact Person Contact Address Phone # Fax # Email Address Cultural Affiliation Last Updated Cahuilla Band of Indians F Anthony Madrigal, Tribal Historic Preservation Officer
52701 CA Highway 371
Anza, CA, 92539
(951) 763-5549 [email protected] Cahuilla 6/28/2023 Cahuilla Band of Indians F Erica Schenk, Chairperson 52701 CA Highway 371 Anza, CA, 92539
(951) 590-0942 (951) 763-2808 [email protected] Cahuilla 2/1/2024 Cahuilla Band of Indians F BobbyRay Esparza, Cultural
Director
52701 CA Highway 371
Anza, CA, 92539
(951) 763-5549 [email protected] Cahuilla 6/28/2023 Gabrieleno Band of Mission Indians - Kizh
Nation
N Christina Swindall Martinez,
Secretary
P.O. Box 393
Covina, CA, 91723
(844) 390-0787 [email protected] Gabrieleno 8/18/2023 Gabrieleno Band of Mission Indians - Kizh
Nation
N Andrew Salas, Chairperson P.O. Box 393
Covina, CA, 91723
(844) 390-0787 [email protected] Gabrieleno 8/18/2023 Gabrieleno/Tongva San Gabriel Band of
Mission Indians
N Anthony Morales, Chairperson P.O. Box 693
San Gabriel, CA, 91778
(626) 483-3564 (626) 286-1262 [email protected] Gabrieleno 12/4/2023 Gabrielino Tongva Indians of California
Tribal Council
N Christina Conley, Cultural
Resource Administrator
P.O. Box 941078
Simi Valley, CA, 93094
(626) 407-8761 [email protected]
du
Gabrielino 3/16/2023
Gabrielino Tongva Indians of California
Tribal Council
N Robert Dorame, Chairperson P.O. Box 490
Bellflower, CA, 90707
(562) 761-6417 (562) 761-6417 [email protected] Gabrielino 3/16/2023 Gabrielino/Tongva Nation N Sandonne Goad, Chairperson 13191 Crossroads Parkway North, Suite 375
City of Industry, CA, 91746
(951) 807-0479 [email protected] Gabrielino 11/6/2025 Gabrielino-Tongva Tribe N Sam Dunlap, Cultural Resource Director
P.O. Box 3919
Seal Beach, CA, 90740
(909) 262-9351 [email protected] Gabrielino 5/30/2023 Gabrielino-Tongva Tribe N Charles Alvarez, Chairperson 23454 Vanowen Street West Hills, CA, 91307
(310) 403-6048 [email protected] Gabrielino 5/30/2023 Juaneno Band of Mission Indians N Sonia Johnston, Chairperson P.O. Box 25628 Santa Ana, CA, 92799
[email protected] Juaneno
Juaneno Band of Mission Indians
Acjachemen Nation - Belardes
N Joyce Perry, Cultural Resource
Director
4955 Paseo Segovia
Irvine, CA, 92603
(949) 293-8522 [email protected] Juaneno 3/17/2023
Juaneno Band of Mission Indians
Acjachemen Nation 84A
N Shannon Wingfield, Secretary 31411-A La Matanza Street San Juan Capistrano, CA, 92675
(949) 488-3484 Juaneno 2/4/2025
Juaneno Band of Mission Indians
Acjachemen Nation 84A
N Heidi Lucero, THPO/MLD 31411-A La Matanza Street
San Juan Capistrano, CA, 92675
(562) 879-2884 [email protected] Juaneno 2/4/2025
Juaneno Band of Mission Indians
Acjachemen Nation 84A
N Nathan Banda, Chairman 31411-A La Matanza Street
San Juan Capistrano, CA, 92675
(949) 426-8804 [email protected] Juaneno 2/4/2025
La Jolla Band of Luiseno Indians F Wesley Ruise, Tribal Chairman 22000 Highway 76 Pauma Valley, CA, 92061
(760) 742-3771 [email protected] Luiseno 5/19/2025 Pala Band of Mission Indians F Alexis Wallick, Assistant THPO PMB 50, 35008 Pala Temecula Road
Pala, CA, 92059
(760) 891-3537 [email protected] Cupeno
Luiseno
11/27/2023
Pala Band of Mission Indians F Shasta Gaughen, Tribal Historic Preservation Officer
PMB 50, 35008 Pala Temecula
Road
Pala, CA, 92059
(760) 891-3515 [email protected] Cupeno
Luiseno
11/27/2023
Pala Band of Mission Indians F Christopher Nejo, Legal
Analyst/Researcher
PMB 50, 35008 Pala Temecula
Road
Pala, CA, 92059
(760) 891-3564 [email protected] Cupeno
Luiseno
11/27/2023
Pauma Band of Luiseno Indians F Lucia Majel, Pauma Cultural Resource Project Manager
P.O. Box 369
Pauma Valley, CA, 92061
(760) 742-1289 [email protected] Luiseno 8/1/2025
Santa Rosa Band of Cahuilla Indians F Steven Estrada, Tribal Chairman P.O. Box 391820 Anza, CA, 92539
(951) 659-2700 (951) 659-2228 [email protected] Cahuilla 4/8/2024 Santa Rosa Band of Cahuilla Indians F Mercedes Estrada, Cultural Director
P.O. Box 391820
Anza, CA, 92539
(951) 659-2700 (951) 659-2228 [email protected] Cahuilla 5/21/2025 Santa Rosa Band of Cahuilla Indians F Vanessa Minott, Tribal Administrator
P.O. Box 391820
Anza, CA, 92539
(951) 659-2700 (951) 659-2228 [email protected] Cahuilla 4/8/2024 Soboba Band of Luiseno Indians F Jessica Valdez, Cultural Resource Specialist
P.O. Box 487
San Jacinto, CA, 92581
(951) 663-6261 (951) 654-4198 [email protected] Cahuilla Luiseno
7/14/2023
Soboba Band of Luiseno Indians F Joseph Ontiveros, Tribal Historic Preservation Officer
P.O. Box 487
San Jacinto, CA, 92581
(951) 663-5279 (951) 654-4198 [email protected] Cahuilla Luiseno
7/14/2023
Imperial,Los Angeles,Orange,Riverside,San
Bernardino,San Diego
Imperial,Los Angeles,Orange,Riverside,San
Bernardino,San Diego
Imperial,Los Angeles,Orange,Riverside,San
Bernardino,San Diego
This list is current only as of the date of this document. Distribution of this list does not relieve any person of statutory responsibility as defined in Section 7050.5 of the Health and Safety Code, Section 5097.94 of the Public Resources Code and Section 5097.98 of the Public Resources Code.

This list is only applicable for contacting local Native Americans with regard to cultural resources assessment for the proposed Foothill Ranch Desktop Review Project, Orange County.

Record: PROJ-2025-006301
Report Type: List of Tribes
Counties: Orange
NAHC Group: All
Orange,Riverside,San Bernardino,San Diego
Orange,Riverside,San Bernardino,San Diego
Los Angeles,Orange,Riverside,San
Bernardino,San Diego,Ventura
Imperial,Los Angeles,Orange,Riverside,San
Bernardino,San Diego
Imperial,Los Angeles,Orange,Riverside,San
Bernardino,San Diego
Los Angeles,Orange,Riverside,San
Bernardino,San Diego
Los Angeles,Orange,Riverside,San
Bernardino,San Diego
Los Angeles,Orange,Riverside,San
Bernardino,San Diego
Orange,Riverside,San Diego
Orange,Riverside,San Bernardino,San Diego
Los Angeles,Orange,Riverside,San
Bernardino,Santa Barbara,Ventura
Los Angeles,Orange,Riverside,San
Bernardino,Santa Barbara,Ventura
Los Angeles,Orange,Riverside,San
Bernardino,Santa Barbara,Ventura
Orange,Riverside,San Diego
Los Angeles,Orange,Riverside,San
Bernardino,San Diego
Los Angeles,Orange,Riverside,San
Bernardino,Santa Barbara,Ventura
Los Angeles,Orange,Riverside,San
Bernardino,Santa Barbara,Ventura
Los Angeles,Orange,Riverside,San
Bernardino,Santa Barbara,Ventura
Los Angeles,Orange,Riverside,San
Bernardino,Santa Barbara,Ventura
Los Angeles,Orange,Riverside,San
Bernardino,Santa Barbara,Ventura
Native American Heritage Commission
Native American Contact List
Orange County
11/14/2025
Counties
Imperial,Los Angeles,Orange,Riverside,San
Bernardino,San Diego
Imperial,Los Angeles,Orange,Riverside,San
Bernardino,San Diego
Imperial,Los Angeles,Orange,Riverside,San
Bernardino,San Diego
11/14/2025 02:19 PM
1 of 1
Item: 11
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Costco Wholesale Project
CEQA Guidelines 15183 | Environmental Compliance Checklist Appendix C
Appendix C – Energy Report

Item: 11
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DRAFT
Prepared for
Costco Wholesale Corporation
Prepared by
Ramboll Americas Engineering Solutions, Inc.

Irvine, California
Project Number
1940111785
Date
December 2025

FOOTHILL RANCH COSTCO PROJECT

ENERGY TECHNICAL REPORT

LAKE FOREST, CALIFORNIA
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Contents Ramboll

CONTENTS
Page

1. INTRODUCTION 1

1.1 Existing Conditions 1

1.2 Proposed Project 1

2. ENERGY ENVIRONMENTAL AND REGULATORY OVERVIEW 2

2.1 General Setting 2

2.1.1 Energy Production and Distribution 2

2.1.2 Energy Consumption 3

2.2 Regulatory Overview 4

2.2.1 Federal Programs 4

2.2.2 State Programs 8

2.2.3 Local Programs 17

3. SIGNIFICANCE THRESHOLDS 19

4. METHODOLOGY FOR DEVELOPMENT OF ENERGY PROJECTIONS 21

4.1 Construction Equipment & Activities 21

4.2 Operational Energy Requirements 22

4.2.1 Electricity 22

4.2.2 Natural Gas 22

4.2.3 Mobile Source Fuel Usage 22

4.2.4 Landscape Equipment Fuel Usage 23

4.2.5 Stationary Source Fuel Usage 23

5. PROJECT INVENTORY IN CONTEXT 24

5.1 Threshold 1 24

5.1.1 Energy Requirements and Energy Use Efficiencies 24

5.1.2 Local and Regional Energy Supplies 25

5.1.3 Peak and Base Period Demands 26

5.1.4 Existing Energy Standards 27

5.1.5 Energy Resources 28

5.1.6 Transportation Energy Use 29

5.1.7 Summary 29

5.2 Threshold 2 29
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CONTENTS (Continued)
TABLES
Table 4-1: Off-Road Equipment Fuel Consumption During Construction Table 4-2: On-Road Vehicle Fuel Consumption During Construction Table 4-3: Operational Electricity Consumption
Table 4-4: Operational Natural Gas Consumption
Table 4-5: Operational Mobile Source Fleet Mixes
Table 4-6: Operational Mobile Source Gasoline Consumption Table 4-7: Operational Mobile Source Natural Gas Consumption Table 4-8: Operational Mobile Source Diesel Consumption Table 4-9: Operational Mobile Source Electricity Consumption Table 4-10: Operational Landscape Equipment Gasoline Consumption Table 4-11: Operational Emergency Generator Natural Gas Consumption Table 5-1: Energy Resource Summary for Construction
Table 5-2: Energy Resource Summary for Proposed Project Operation

APPENDICIES
Appendix A: Project Evaluation Against State and Local Plans Item: 11
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Acronym and Abbreviations Ramboll

ACRONYMS AND ABBREVIATIONS
Acronym Definition
AB Assembly Bill
ACC Advanced Clean Cars
ACF Advanced Clean Fleets
ACT Advanced Clean Trucks
ADA Americans with Disabilities Act
ATCM Airborne Toxic Control Measure
CalEEMod® California Emissions Estimator Model®
CalGreen California Green Building Standards Code
CARB California Air Resources Board
CEC California Energy Commission
CEQA California Environmental Quality Act
CO2 carbon dioxide
EO Executive Order
EV Electric vehicle
GHG greenhouse gas
GWh gigawatt hours
IEPR Integrated Energy Policy Report
ISTEA Intermodal Surface Transportation Efficiency Act
kWh kilowatt hours
LCFS Low Carbon Fuel Standard
LEV low-emission vehicle
mpg miles per gallon
MPO Metropolitan Planning Organization
MW megawatt
MWh megawatt hours
NHTSA National Highway Traffic Safety Administration
NOx Oxides of Nitrogen
RPS Renewables Portfolio Standard
SAFE Safer Affordable Fuel-Efficient
SB Senate Bill
SCAG Southern California Association of Governments
SCE Southern California Edison
SCS Sustainable Communities Strategy
TEA Transportation Equity Act
TRU Transport Refrigeration Units
USEPA United States Environmental Protection Agency
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ACRONYMS AND ABBREVIATIONS (Continued)
Acronym Definition
VMT vehicle miles traveled
ZEV zero-emission vehicle
ZNE Zero Net Energy
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1. INTRODUCTION
Ramboll Americas Engineering Solutions, Inc. (Ramboll) was retained to prepare an Energy Technical Report for the proposed Foothill Ranch Costco Project (Project) located at 26602 Towne Centre Drive, Foothill Ranch, California. The Project is located along State Route 241 between Bake Parkway and Alton Parkway within the Foothill Ranch Specific Planned Community at APN 612-093-13 This Energy Technical Report analyzes the energy impacts of the proposed Project’s construction and operation activities. In particular, this report describes the existing setting of the Project site, describes the relevant regulatory setting, discusses the methodology used to evaluate energy emissions related to the Project, and evaluates potential impacts related to energy that would be affected as a result of implementation of the proposed Project.

1.1 Existing Conditions
The site is currently designated as the Foothill Ranch Towne Centre Shopping Mall. Existing conditions of the site consist of one building surrounded by an asphalt pavement parking lot and landscape islands, the existing building served as a Regal Cinemas theater.

1.2 Proposed Project
Project scope includes demolition of approximately 16.3 acres of the existing asphalt pavement and landscaping, and removal of one (1) building located within Foothill Ranch Towne Centre. Proposed improvements include construction of a new ground up Costco Wholesale Membership Warehouse Building. The 35-foot-tall building will have a footprint of approximately 165,068 square feet with architectural enhancements. The parking lot will consist of surface parking and landscape planters. The current site plan proposes 913 stalls.

Existing underground utilities will also be removed to install new underground utilities to meet the Project site demands as it relates to stormwater, domestic water, fire water, sanitary sewer, and dry utilities. Truck ingress access will be provided from Towne Centre Drive, follow the north drive aisle along the property boundary, travel south along the west side of the building to the loading dock. Truck egress will follow the site’s proposed outer drive aisle, not interfering with the building’s main entrance.

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2. ENERGY ENVIRONMENTAL AND REGULATORY

OVERVIEW

2.1 General Setting

2.1.1 Energy Production and Distribution
Among the states, California ranks eighth in the nation in production of crude oil, fifteenth in production of natural gas, second in generation of conventional hydroelectric power, second in the production of electricity from biomass, and first in the production of electricity from geothermal and solar energy.1 California produces approximately 10% of the natural gas used in the state and imports approximately 90% from Canada, the Southwest, and the Rocky Mountains region of the United States.2 Approximately two-thirds of the crude oil refined in California is from foreign countries, including Iraq, Brazil, Guyana, and Ecuador.3 Additional crude oil is imported from Alaska.4 One-fifth to one-third of California’s annual electricity supply is from outside the state.5
Electricity Supply
The production of electricity requires the combustion, consumption, or conversion of other energy resources, including water, wind, oil, natural gas, coal, solar, geothermal, and nuclear. Of the electricity that was generated within the state in 2024, 40% was generated by natural gas-fired power plants, 23.4% by solar, 13.5% by hydroelectric, 8.5% by nuclear power plants, 7.3% by wind, 4.8% by geothermal, 2.2% by biomass, and a remaining

0.3% by other sources.
6 For the Orange County area, Southern California Edison (SCE) is the primary supplier of electricity to businesses and residents of the area. SCE’s 50,000-square-mile service area covers Southern, Central, and Coastal California. In 2023, approximately 40.4% of SCE’s electricity provided to its customers came from renewable sources and about 51% came from carbon-free resources.
7 Transportation Fuels Supply
Most petroleum fuel refined in California is for use in on-road motor vehicles and is refined within California to meet state-specific formulations required by the California Air Resources Board (CARB). The major categories of petroleum fuels are gasoline and diesel for passenger vehicles, transit, and rail vehicles and fuel oil for industry and emergency electrical power 1 U.S. Energy Information Administration. 2025. California State Profile and Energy Estimates: Profile Overview.

Available at: http://www.eia.gov/state/?sid=CA. Accessed: October 2025. 2 Ibid.
3 Ibid.
4 Ibid.
5 Ibid.
6 California Energy Commission. 2024. 2024 Total System Electric Generation in Gigawatt Hours. Available at:
https://www.energy.ca.gov/data-reports/energy-almanac/california-electricity-data/2024-total-system-electricgeneration. Accessed: October 2025. 7 Southern California Edison (SCE). 2024 Sustainability Report. Available at:
https://download.edison.com/406/files/20255/202506060031/2024%20Sustainability%20Report.pdf.

Accessed: October 2025.

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generation. Other liquid fuels include kerosene, jet fuel, and residual fuel oil for marine vessels.

California’s oil fields make it the eighth-largest petroleum-producing state in the United States, after Texas, New Mexico, North Dakota, Colorado, Alaska, Oklahoma, and Wyoming. 8 Crude oil is transported within California through a network of pipelines that carry it from both onshore and offshore oil wells to the refineries that are located in the San Francisco Bay Area, the Los Angeles area, and the Central Valley. Currently, 13 petroleum refineries operate in California, processing approximately 1.6 million barrels per day of crude oil.9 Other transportation fuel sources are alternative fuels, such as methanol and denatured ethanol (alcohol mixtures that contain no less than 70% alcohol), natural gas (compressed or liquefied), liquefied petroleum gas, hydrogen, and fuels derived from biological materials (i.e., biomass).

2.1.2 Energy Consumption
Electricity Consumption
Californians consumed 282,783 gigawatt hours (GWh) of electricity in 2024. 10,11 Of this total,
Orange County consumed 19,225 GWh.12
Transportation Sector Fuels Consumption
The transportation sector is a major end use of energy in California, accounting for approximately 44.5% of total state-wide energy consumption in 2023, the most recent year for which data is available.13 In addition, there is energy consumption associated with construction and maintenance of transportation infrastructure, such as streets, highways, freeways, rail lines, and airport runways.
8 U.S. EIA. 2025. Rankings: Crude Oil Projection, June 2025 (thousand barrels per day). Available at:
https://www.eia.gov/state/rankings/?sid=CA#series/46. Accessed: October 2025. 9 U.S. EIA. 2025. Petroleum & Other Liquids. Number and Capacity of Petroleum Refineries. June 20. Available at:
https://www.eia.gov/dnav/pet/PET_PNP_CAP1_DCU_SCA_A.htm. Accessed: October 2025. 10 A watt hour is a unit of energy equivalent to one watt of power expended for one hour. For example, a typical light bulb is 60 watts, meaning that if it is left on for one hour, 60-watt hours have been used. One kilowatt equals 1,000 watts. The consumption of electrical energy by homes and businesses is usually measured in kilowatt hours (kWh). Some large businesses and institutions also use megawatt hours (MWh), where one MWh equals 1,000 kWh. One gigawatt equals one thousand (1,000) megawatts, or one million (1,000,000) kilowatts. The energy output of large power plants over long periods of time, or the energy consumption of jurisdictions, can be expressed in GWh.
11 Electricity data for Orange County and the State of California in 2024 are obtained from the California Energy Commission, Energy Consumption Data Files. Available at: https://www.energy.ca.gov/files/energyconsumption-data-files. Accessed: October 2025. 12 Ibid.
13 U.S. Energy Information Administration. 2023. California State Profile and Energy Estimates: California Energy Consumption by End-Use Sector, 2023. Available at: http://www.eia.gov/state/?sid=CA#tabs-2. Accessed:

October 2025.

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2.2 Regulatory Overview

2.2.1 Federal Programs

2.2.1.1 Energy Policy and Conservation Act
The Energy Policy and Conservation Act of 1975 was established in response to the oil crisis of 1973, which increased oil prices due to a shortage of reserves. The Act requires that all vehicles sold in the U.S. meet certain fuel economy goals, known as the Corporate Average Fuel Economy standards. The National Highway Traffic Safety Administration (NHTSA) of the U.S. Department of Transportation administers the Corporate Average Fuel Economy program, and the U.S. Environmental Protection Agency provides the fuel economy data.

In April 2010, the United States Environmental Protection Agency (USEPA) and NHTSA issued a final rulemaking establishing new federal fuel economy standards for model years 2012 to 2016 passenger cars and light-duty trucks. For model year 2012, the fuel economy standards for passenger cars, light trucks, and combined cars and trucks were

33.3 miles per gallon (mpg), 25.4 mpg, and 29.7 mpg, respectively.14 These standards increase progressively up to 37.8 mpg, 28.8 mpg, and 34.1, respectively, for model year 2016. In subsequent rulemakings, the agencies extended the national program of fuel economy standards to passenger vehicles and light-duty trucks of model years 2017-2025, culminating in fuel economy of 54.5 mpg by model year 2025. 15 Additionally fuel economy
standards for medium- and heavy-duty vehicles including large pickup trucks and vans, semi-trucks, and all types and sizes of work trucks and buses, were established for model years 2014-2018 (Advanced Fuel Economy and Greenhouse Gas (GHG) Standard – Phase 1).
16 In August 2016, the USEPA and NHTSA adopted the next phase (Phase 2) of the fuel economy and greenhouse gas (GHG) standards for medium- and heavy-duty trucks, which apply to vehicles with model year 2018 and later.17 In response to the USEPA’s adoption of the Phase 2 standards, CARB staff brought a proposed California Phase 2 program before its Board in 2017; and the Board approved the program in March 2018.18 In 2018, the USEPA and NHTSA proposed to amend certain existing Corporate Average Fuel Economy standards for passenger cars and light trucks and establish new standards, covering model years 2021-2026. Compared to maintaining the post-2020 standards now in place, the proposal would increase U.S. fuel consumption.19 14 USEPA and DOT. 2010. Light-Duty Vehicle Greenhouse Gas Emission Standards and Corporate Average Fuel Economy Standards. Final Rule. 75 Fed. Reg. 25324-25728. 15 USEPA and DOT. 2012. 2017 and Later Model Year Light-Duty Vehicle Greenhouse Gas Emissions and Corporate Average Fuel Economy Standards; Final Rule. 77 Fed. Reg. 62623. 16 USEPA and DOT. 2011. Greenhouse Gas Emissions Standards and Fuel Efficiency Standards for Medium- and Heavy-Duty Engines and Vehicles. 76 Fed. Reg. 57106.
17 USEPA. Available at: https://www.epa.gov/regulations-emissions-vehicles-and-engines/final-rule-greenhousegas-emissions-and-fuel-efficiency. Accessed: October 2025. 18 CARB. California Phase 2 Greenhouse Gas Standards. Available at: https://ww2.arb.ca.gov/ourwork/programs/greenhouse-gas-standards-medium-and-heavy-duty-engines-and-vehicles/phase2. Accessed:

October 2025.
19 Federal Register. 2018. The SAFE Vehicles Rule for Model Years 2021-2026 Passenger Cars and Light Trucks.

Available at: https://www.federalregister.gov/documents/2018/08/24/2018-16820/the-safer-affordable-fuelefficient-safe-vehicles-rule-for-model-years-2021-2026-passenger-cars-and. Accessed: October 2025.

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In 2019, the USEPA and NHTSA announced the One National Program Rule, which allows the federal government to set the standard for uniform fuel economy and GHG emissions of automobiles and light-duty trucks. USEPA withdrew the Clean Air Act pre-emption waiver it granted to the State of California as it related to California’s GHG and zero-emission vehicles (ZEVs) programs.
20 On the first day of the Biden Administration, the President signed Executive Order 13990, 21 which directed NHTSA and USEPA to immediately review and consider suspending or rescinding the Safer Affordable Fuel-Efficient (SAFE) I Rule. On April 28, 2021, USEPA published a notice regarding reconsideration of a prior action that withdrew a waiver of pre-emption for California’s zero-emission vehicle mandate and GHG emission standards. On May 12, 2021, the NHTSA published a notice of proposed rulemaking, proposing to repeal key portions of the SAFE Rule Part I. A virtual public hearing for USEPA’s Notice of Reconsideration of SAFE I was held on June 2, 2021. The NHTSA finalized the Corporate Average Fuel Economy Pre-emption rulemaking to withdraw its portions of the SAFE I Rule on December 21, 2021.22 On March 9, 2022, USEPA reinstated California’s authority under the Clean Air Act to implement its own GHG emission standards and ZEVs sales mandate and entirely rescinded the SAFE Rule (Part One).

In December 2021, USEPA finalized revised national GHG emissions standards for passenger cars and light trucks for model years 2023-2026.
23 These standards are the strongest vehicle
emissions standards established for the light-duty vehicle sector and will result in avoiding more than 3 billion tons of GHG emissions through 2050.

In April 2023, the USEPA proposed a new more ambitious proposed standards for national GHG emission standards from light-duty and medium-duty vehicles starting with 2027 model year vehicles.24 On March 20, 2024, USEPA finalized these standards, which will phase in over model years 2027 to 2032. These standards build upon existing rules, and leverage advances in clean car technology to realize benefits to Americans such as the improvement of public health through reduction of criteria air pollutant and GHG emissions from vehicles.25 On August 5, 2021, USEPA announced plans to reduce GHG emissions and other harmful air pollutants from heavy-duty trucks through a series of rulemakings over the next three years. 20 USEPA. 2019. Trump Administration Announces One National Program Rule on Federal Preemption of State Fuel Economy Standards. Available at: https://www.epa.gov/newsreleases/trump-administration-announces-onenational-program-rule-federal-preemption-state-fuel. Accessed: October 2025. 21 Executive Office of the President. Executive Order 13990. 2021. Available at:
https://www.federalregister.gov/documents/2021/01/25/2021-01765/protecting-public-health-and-theenvironment-and-restoring-science-to-tackle-the-climate-crisis. Accessed: October 2025. 22 NHTSA. Available at: https://www.nhtsa.gov/laws-regulations/corporate-average-fuel-economy. Accessed:

October 2025.
23 USEPA. 2021. Final Rule to Revise Existing National GHG Emissions Standards for Passenger Cars and Light Trucks Through Model Year 2026. Available at: https://www.epa.gov/regulations-emissions-vehicles-andengines/final-rule-revise-existing-national-ghg-emissions. Accessed: October 2025. 24 USEPA. 2023. Proposed Rule: Multi-Pollutant Emissions Standards for Model Years 2027 and Later Light-Duty and Medium-Duty Vehicles. Available at: https://www.epa.gov/regulations-emissions-vehicles-andengines/proposed-rule-multi-pollutant-emissions-standards-model. Accessed: October 2025. 25 USEPA. 2023. Final Rule: Multi-Pollutant Emissions Standards for Model Years 2027 and Later Light-Duty and Medium-Duty Vehicles. Available at: https://www.epa.gov/regulations-emissions-vehicles-and-engines/finalrule-multi-pollutant-emissions-standards-model. Accessed: October 2025.

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The first rulemaking of this Clean Trucks Plan is a final rule signed on December 20, 2022, which focuses on reducing emissions that form smog and soot and will apply to heavy-duty engines and vehicles beginning in model year 2027.26
On January 20, 2025, newly re-elected President Trump issued an Executive Order (14148) entitled Initial Rescissions of Harmful Executive Orders and Actions, which revokes Biden-era Executive Order 14037 that directed the USEPA and the Secretary of Transportation to consider beginning work on rulemakings to establish vehicle emissions standards and fuel economy standards for vehicles with model years 2027 and later. Executive Order 14148 directed NHTSA to commence review and reconsideration of all existing fuel economy standards for vehicle model years 2022 and later.27
In December 2024, USEPA granted waivers for Advanced Clean Cars II (ACC II) Regulations, the heavy-Duty Engine Vehicle Omnibus Low NOX Regulation, the Small Off-Road Engines Regulations. In January 2025, the waiver for the In-Use Off-Road Diesel-Fueled Fleets regulations was issued by the USEPA. Also in January 2025, USEPA granted partial authorizations for the 2022 amendments to the Commercial Harbor Craft Regulations and the amendments to the In-Use Diesel-Fueled Transport Refrigeration Units (TRU) and TRU Generator Sets regulations. In addition, CARB withdrew its requests for waivers for the In-Use Locomotive Standards, the Advanced Clean Fleets Regulation, portions of the Commercial Harbor Craft and Ocean-Going Vessels At-Berth, and the Transport Refrigeration Unit Engine Standards that were not authorized by the USEPA in January 2025. 28 In May 2025, the United States Congress and Senate voted to disapprove California’s Clean Air Act waivers for ACC II, Advanced Clean Trucks (ACT), and the heavy-Duty Engine Vehicle Omnibus Low NOX Regulation using the Congressional Review Act. In response to this action, CARB stated that they “will pursue every available remedy to challenge these actions”.29

2.2.1.2 Energy Policy Act of 2005 and Energy Independence and Security Act of 2007
The Energy Policy Act of 2005 seeks to reduce reliance on non-renewable energy resources and provide incentives to reduce current demand on these resources. For example, under the Energy Policy Act, consumers and businesses can attain federal tax credits for purchasing fuel-efficient appliances and products. Because driving fuel-efficient vehicles and installing energy efficient appliances can provide many benefits, such as lower energy bills, increased indoor comfort, and reduced air pollution, businesses are eligible for tax credits for buying 26 USEPA. Regulations for Emissions from Vehicles and Engines. Available at: https://www.epa.gov/regulationsemissions-vehicles-and-engines/regulations-greenhouse-gas-emissions-commercial-trucks. Accessed: October 2025.
27 USDOT. 2025. Memorandum to Office of the Administrator of the National Highway Traffic Safety Administration (NHTSA), Office of the Assistant Secretary of Policy (OST-P) and Office of the General Counsel (OGC), Subject: Fixing the CAFE Program. January 28. Available at:
https://www.transportation.gov/sites/dot.gov/files/2025- 01/Signed%20Secretarial%20Memo%20re%20Fixing%20the%20CAFE%20Program.pdf. Accessed: October 2025.
28 USEPA. Vehicle Emissions California Waivers and Authorizations. Available at: https://www.epa.gov/state-andlocal-transportation/vehicle-emissions-california-waivers-and-authorizations. Accessed: October 2025. 29 CARB. CARB Chair Liane Randolph responds to illegal and unconstitutional approval of Congressional Review Act resolutions by the U. S. Senate. Available at: https://ww2.arb.ca.gov/news/carb-chair-liane-randolph-respondsillegal-and-unconstitutional-approval-congressional-review. Accessed: October 2025.

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hybrid vehicles, building energy efficient buildings, and improving the energy efficiency of commercial buildings. Additionally, tax credits are given for the installation of qualified fuel cells, stationary microturbine power plants, and solar power equipment.

The Energy Policy Act of 2005 also established the first renewable fuel volume mandate in the United States. The original Renewable Fuel Standard program required 7.5 billion gallons of renewable fuel to be blended into gasoline by 2012. Under the Energy Independence and Security Act of 2007, the Renewable Fuel Standard program was expanded to include diesel and to increase the volume of renewable fuel required to be blended into transportation fuel from 9 billion gallons in 2008 to 36 billion gallons by 2022.

2.2.1.3 American Recovery and Reinvestment Act
The American Recovery and Reinvestment Act of 2009 was passed in response to the economic crisis of the late 2000s, with the primary purpose of maintaining existing jobs and creating new jobs. Among the secondary objectives of the American Recovery and Reinvestment Act was investment in “green” energy programs, including funding the following through grants, loans, or other mechanisms: private companies developing renewable energy technologies; local and state governments implementing energy efficiency and clean energy programs; research in renewable energy, biofuels, and carbon capture; and development of high-efficiency or electric vehicles.30

2.2.1.4 Intermodal Surface Transportation Efficiency Act The Intermodal Surface Transportation Efficiency Act (ISTEA) of 1991 promotes the development of intermodal transportation systems to maximize mobility as well as address national and local interests in air quality and energy. The ISTEA contains factors that metropolitan planning organizations (MPO) are to address in developing transportation plans and programs, including some energy-related factors. To meet the ISTEA requirements, MPOs have adopted explicit policies defining the social, economic, energy, and environmental values that guide transportation decisions in their respective metropolitan areas. The planning process for specific projects would then address these policies. Another requirement of the ISTEA is to consider the consistency of transportation planning with federal, state, and local energy goals. Through this requirement, energy consumption is expected to be a decision criterion, along with cost and other values to determine the best transportation solution.

2.2.1.5 Transportation Equity Act for the 21st Century
The Transportation Equity Act for the 21st Century (“TEA-21”) was signed into law in 1998 and builds upon the initiatives established in the ISTEA legislation discussed above.

TEA-21 authorizes highway, highway safety, transit, and other efficient surface transportation programs. TEA-21 continues the program structure established for highways and transit under ISTEA, such as flexibility in the use of funds, emphasis on measures to improve the environment, and focus on a strong planning process as the foundation of good transportation decisions. TEA-21 also provides for investment in research and its application to maximize the performance of the transportation system through, for example, deployment of Intelligent Transportation Systems, to help improve operations and management of transportation systems and vehicle safety.
30 USEPA. 2009. Recovery: EPA Gets Involved. Available at: https://archive.epa.gov/recovery/web/html/. https://archive.epa.gov/recovery/web/html/ Accessed: October 2025.

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2.2.2 State Programs

2.2.2.1 AB 32, SB 32, and AB 1279 (State-wide GHG Reductions with Energy Co-Benefits)
The California Global Warming Solutions Act of 2006 (Assembly Bill [AB] 32) was signed into law in September 2006.31 The law instructed CARB to develop and enforce regulations for the reporting and verification of state-wide GHG emissions. The bulk of GHG emissions in California are carbon dioxide that result from fossil fuel consumption. Therefore, a reduction in GHG emissions typically translates into reduced fuel and increased energy efficiency. The bill directed CARB to set a state-wide GHG emission limit based on 1990 levels, to be achieved by 2020.

AB 32 requires CARB to adopt rules and regulations in an open public process to achieve the maximum technologically feasible and cost-effective GHG reductions. In December 2008, CARB adopted its Climate Change Scoping Plan: A Framework for Change (Scoping Plan), which included the state’s strategies for achieving AB 32’s reduction targets. These strategies are implemented with additional rules and regulations of relevance to energy analysis, such as the Advanced Clean Cars (ACC) Program, the Low Carbon Fuel Standard (LCFS), Title 24 building efficiency standards, and the Renewables Portfolio Standard (RPS).

These are discussed further below.

Enacted in 2016, Senate Bill (SB) 32 (Pavley, 2016) codifies a 2030 GHG emissions reduction goal and requires CARB to ensure that state-wide GHG emissions are reduced to 40 percent below 1990 levels by 2030. Similar to AB 32, a reduction in GHG emissions typically corresponds with a reduction in energy usage as the bulk of GHGs result from the combustion of fossil fuel.

Lastly, AB 1279 was enacted by the California Legislature in September 2022 and established that the state must achieve carbon neutrality as soon as possible, but no later than 2045, and maintain net negative GHG emissions thereafter. Additionally, AB 1279 required that by 2045 state-wide anthropogenic GHG emissions be reduced by at least 85 percent below 1990 levels. As noted above for AB 32 and SB 32, a reduction in GHG emissions typically corresponds with a reduction in energy usage.

2.2.2.2 SB 350 (Clean Energy and Pollution Reduction Act of 2015) The Clean Energy and Pollution Reduction Act of 2015 (SB 350) increases California's renewable electricity procurement goal from 33 percent by 2020 to 50 percent by 2030. This bill requires the State Energy Resources Conservation and Development Commission to establish annual targets for state-wide energy efficiency savings and demand reduction that will achieve a cumulative doubling of state-wide energy efficiency savings in electricity and natural gas final end uses of retail customers by January 1, 2030.

2.2.2.3 2023 Integrated Energy Policy Report
The 2023 Integrated Energy Policy Report (IEPR) provides an assessment of major energy trends and issues for a variety of energy sectors, as well as policy recommendations.32 31 CARB. Assembly Bill 32 Overview. 2006. Available at: http://www.arb.ca.gov/cc/ab32/ab32.htm. Accessed:

October 2025.
32 California Energy Commission. 2023. 2023 Integrated Energy Policy Report. Available at:
https://www.energy.ca.gov/data-reports/reports/integrated-energy-policy-report/2023-integrated-energypolicy-report. Accessed: October 2025.

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Prepared by the California Energy Commission (CEC), this report details the key energy issues facing California and develops potential strategies to address these issues. The 2023 IEPR includes a discussion of electricity resources and demand, accelerating and enhancing the energy grid, and potential use of hydrogen. The assessments and forecasted energy demand within this report will be used by the CEC to develop future energy policies.

As of September 2025, the 2024 IEPR Update is available and in the process of consideration for adoption.33

2.2.2.4 Title 24 Building Energy Efficiency Standards
The California Green Building Standards Code, as specified in Title 24, Part 11 of the California Code of Regulations, commonly referred to as CalGreen Building Standards (CalGreen), establishes voluntary and mandatory standards to improve public health, safety, and general welfare by enhancing the design and construction of buildings through the use of building concepts having a positive environmental impact and encouraging sustainable construction practices in five categories: planning and design, energy efficiency, water efficiency and conservation, material conservation and resource efficiency, and environmental quality. The provisions of this code apply to the planning, design, operation, construction, replacement, use and occupancy, location, maintenance, removal and demolition of every building or structure or any appurtenances connected or attached to such building structures throughout California. Examples of CalGreen provisions include reducing indoor water use, moisture sensing irrigation systems for landscaped areas, construction waste diversion goals, and energy system inspections. CalGreen is periodically amended; the current 2022 standards became effective on January 1, 2023. The 2025 standards will become effective on January 1, 2026.

The Energy Efficiency Standards for Residential and Non-residential Buildings, as specified in Title 24, Part 6, of the California Code of Regulations, were established in 1978 in response to a legislative mandate to reduce California’s energy consumption. The standards are updated periodically to allow consideration and possible incorporation of new energy efficiency technologies and methods for building features such as space conditioning, water heating, lighting, and whole envelope. The 2005, 2008, and 2013 updates to the efficiency standards included provisions such as cool roofs on commercial buildings, increased use of skylights, and higher efficiency lighting, HVAC, and water heating systems. Additionally, some standards focused on larger energy-saving concepts such as reducing loads at peak periods and seasons and improving the quality of such energy-saving installations. Past updates to the Title 24 standards have proven very effective in reducing building energy use, with the 2013 update estimated to reduce energy consumption in residential buildings by 25% and energy consumption in commercial buildings by 30%, relative to the 2008 standards.34 The 2016 updates included additional high-efficiency lighting requirements, high performance attic and walls, and higher efficiency water and space heaters. The 2016 standards were expected to reduce residential electricity consumption by 33 California Energy Commission. 2025. 2024 Integrated Energy Policy Report Update. Available at:
https://www.energy.ca.gov/data-reports/reports/integrated-energy-policy-report-iepr/2024-integrated-energypolicy-report. Accessed: October 2025. 34 CEC. 2012. Energy Commission Approves More Efficient Buildings for California's Future. Available at:
https://planning.lacity.org/eir/CrossroadsHwd/deir/files/references/C17.pdf. Accessed: October 2025.

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The California Public Utilities Commission, CEC, and CARB also have a shared, established goal of achieving Zero Net Energy (ZNE) for new construction in California. The key policy timelines include: (1) all new residential construction in California will be ZNE by 2020, and (2) all new commercial construction in California will be ZNE by 2030. The ZNE goal generally means that new buildings must use a combination of improved efficiency and renewable energy generation to meet 100 percent of their annual energy need, as specifically defined by the CEC:
“A ZNE Code Building is one where the value of the energy produced by on-site renewable energy resources is equal to the value of the energy consumed annually by the building, at the level of a single ‘Project’ seeking development entitlements and building code permits, measured using the [CEC]’s Time Dependent Valuation metric. A ZNE Code Building meets an Energy Use Intensity value designated in the Building Energy Efficiency Standards by building type and climate zone that reflect best practices for highly efficient buildings.”37
While the 2019 Title 24 standards do not achieve the 2020 ZNE goal, they do move the state further along the path to achieving this goal. The CEC has more recently focused on grid harmonization strategies, to bring maximum benefits to the grid, environment, and occupants; and GHG emissions reductions.38
The 2022 Title 24 Building Energy Efficiency Standards (2022 Energy Code) are the currently applicable Building Energy Efficiency Standards and became effective on January 1, 2023.39 The 2022 Energy Code updates include the encouragement of efficient electric heat pump usage for space heating and water heating, establishing electric-ready requirements for new homes, and strengthening ventilation standards. For the first time in the United States, this update also includes solar-electric systems in addition to battery systems as the performance 35 CEC. 2015. 2016 Building Energy Efficiency Standards Adoption Hearing. Available at:
https://web.archive.org/web/20190602115405/http://www.energy.ca.gov/title24/2016standards/rulemaking/do cuments/2015-06-10_hearing/2015-06-10_Adoption_Hearing_Presentation.pdf. Accessed: October 2025. 36 CEC. 2018. 2019 Title 24 Impact Analysis. June. Available at:
https://web.archive.org/web/20190601203553/https://www.energy.ca.gov/title24/2019standards/post_adoptio n/documents/2019_Impact_Analysis_Final_Report_2018-06-29.pdf. Accessed: October 2025. 37 CEC, 2015 Integrated Energy Policy Report (2015), p. 41. 38 CEC. 2018. The 2019 Building Energy Efficiency Standards ZNE Strategy. September 11. Available at:
https://www.cesa.org/wp-content/uploads/CESA-webinar-slides-9.11.2018.pdf. Accessed: October 2025. 39 CEC. 2022. 2022 Building Energy Efficiency Standards. Available at: https://www.energy.ca.gov/programs-andtopics/programs/building-energy-efficiency-standards/2022-building-energy-efficiency. Accessed: October 2025.

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The 2025 Building Energy Efficiency Standards (2025 Energy Code) will expand the use of heat pumps in newly constructed residential buildings, encourage electric-readiness, and further strengthen ventilation standards.41 Buildings whose permit applications are applied for on or after January 1, 2026, must comply with the 2025 Energy Code.

2.2.2.5 Renewables Portfolio Standard
SB 1078 (2002) requires retail sellers of electricity, including investor-owned utilities and community choice aggregators, to obtain at least 20 percent of their energy supply from renewable sources by 2017. SB 107 (2006) changed that target date to 2010. In November 2008, then-Governor Schwarzenegger signed Executive Order S-14-08, which expanded the state’s RPS to 33 percent renewable power by 2020. In April 2011, then-Governor Brown signed SB 2X, which legislated the prior Executive Order S-14-08 renewable standard. SB 350 (2015) set an additional RPS goal of 50 percent renewables by 2030. SB 100 (2018) accelerated and extended again the RPS – requiring achievement of a 50 percent RPS by 2026 and a 60 percent RPS by 2030. SB 100 also established a state policy goal to achieve 100 percent carbon-free electricity by 2045.

2.2.2.6 Mobile Source Regulations
SB 743 (Transportation Analysis Under CEQA)
Public Resources Code Section 21099(c)(1), as codified through enactment of SB 743, was enacted with the intent to change the focus of transportation analyses conducted under the California Environmental Quality Act (CEQA). SB 743 reflects a legislative policy to balance the needs of congestion management with state-wide goals related to infill development, promotion of public health through active transportation, and reduction of GHG emissions. As finalized in December 2018, amendments to the State CEQA Guidelines adopted in furtherance of SB 743 establish vehicle miles traveled (VMT), in lieu of level of service, as the new metric for transportation analysis. Implementation of SB 743 is anticipated to improve the efficiency of transportation fuels consumption.

SB 375 (Land Use Planning)
SB 375, the Sustainable Communities and Climate Protection Act of 2008, supports the state’s climate action goals to reduce GHG emissions through coordinated transportation and land use planning. SB 375 required CARB to establish GHG emission reduction targets (regional targets) for each metropolitan planning region. For the area under SCAG’s jurisdiction, including the Project site, CARB originally adopted regional targets for reduction of mobile source-related GHG emissions of 8% for 2020 and 13% for 2035. The targets are expressed as a percentage change in per capita passenger vehicle GHG emissions relative to 2005 emissions levels. These original targets were in place through September 30, 2018. In March 2018, CARB approved updated regional targets of 8% for 2020 and 19% for 2035 for 40 CEC. 2023. Impact Analysis 2022 Update to the California Energy Code. https://efiling.energy.ca.gov/GetDocument.aspx?tn=250892. Accessed: October 2025. 41 CEC. 2025. 2025 Building Energy Efficiency Standards. Available at: https://www.energy.ca.gov/programs-andtopics/programs/building-energy-efficiency-standards/2025-building-energy-efficiency. Accessed: October 2025.

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Pavley Regulations
AB 1493 (Pavley, 2002) required CARB to adopt regulations to reduce GHG emissions from non-commercial passenger vehicles and light-duty trucks for model years 2009–2016. CARB obtained a waiver from the USEPA that allows for implementation of these regulations notwithstanding possible federal pre-emption concerns.

Low Carbon Fuel Standard
Executive Order (EO) S-1-07, as issued by Governor Schwarzenegger, called for a 10 percent or greater reduction in the average fuel carbon intensity for transportation fuels in California regulated by CARB by 2020.43 In response, CARB approved the LCFS regulations in 2009, which became fully effective in April 2010. Thereafter, a lawsuit was filed challenging CARB’s adoption of the regulations; and, in 2013, a court order was issued compelling CARB to remedy substantive and procedural defects of the LCFS adoption process under CEQA.44 However, the court allowed implementation of the LCFS to continue pending correction of the identified defects. In September 2015, CARB re-adopted the LCFS regulations. The most recent amendments to the LCFS regulation were adopted on November 8, 2024. These amendments would reduce GHG emissions by reducing the carbon intensity of transportation fuels used in California by at least 30% in 2030 and 90% in 2045, as compared to the 2010 baseline.45 Additional amendments have been proposed and presented at hearing on September 25, 2025 and will be further discussed at a hearing on November 20, 2025. The amendments focus on enhancing the LCFS Hydrogen Refueling Infrastructure crediting and expanding near-term low-emission truck fueling options, through allowing indirect accounting for renewable natural gas for LCFS crediting of electricity generated by linear generators.46,47
California’s Advanced Clean Cars
In January 2012, CARB approved the ACC Program, which established an emissions control program for cars and light-duty trucks (such as sport utility vehicles, pickup trucks, and minivans) of model years 2017-2025. When the program is fully implemented, new vehicles 42 CARB. SB 375 Regional Targets. Available at: https://ww2.arb.ca.gov/our-work/programs/sustainablecommunities-program/regional-plan-targets. Accessed: October 2025. 43 Carbon intensity is a measure of the GHG emissions associated with the various production, distribution, and use steps in the “lifecycle” of a transportation fuel.
44 POET, LLC v. CARB (2013) 217 Cal.App.4th 1214.
45 CARB. 2024. Low Carbon Fuel Standard Amendments SCH# 2023020330. Available at:
https://ww2.arb.ca.gov/sites/default/files/barcu/regact/2024/lcfs2024/nod.pdf. Accessed: October 2025. 46 CARB. 2025. Notice of Public Hearing to Consider Proposed Amendments to the Advanced Clean Fleets and Low Carbon Fuel Standard Regulations. Available at:
https://ww2.arb.ca.gov/sites/default/files/barcu/regact/2025/acf_lcfs/notice.pdf. Accessed: October 2025. 47 CARB. 2025. Proposed Amendments to the On-Road Heavy-Duty Engine and Vehicle Omnibus, Low Carbon Fuel Standard Regulations, and to Permanently Adopt the Emergency Vehicle Emissions Regulations. Available at:
https://content.govdelivery.com/accounts/CARB/bulletins/3f3e2ef. Accessed: October 2025.

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Following the Board’s direction to begin development of standards for model years after 2025, ACC II has been prepared to establish the next set of low-emission vehicle (LEV) and ZEV requirements to contribute to meeting federal ambient air quality ozone standards and California’s carbon neutrality targets. The Staff Report: Initial Statement of Reasons for the Public Hearing to Consider the Proposed ACC II Regulations posted in April 2022, and a rulemaking package was presented for the Board hearing date in June 2022. At a second hearing in August 2022 the Board approved the item. ACC II was approved by the Office of Administrative Law on November 30, 2022.

In October 2023, CARB launched a new effort to consider potential amendments to the ACC II regulations, including updates to the tailpipe greenhouse gas emission standard and limited revisions to the LEV and ZEV regulations. On December 18, 2024, USEPA granted a waiver for California’s ACC II regulation.48 In May 2025, the United States Congress and Senate voted to disapprove California’s Clean Air Act waiver for ACC II regulation. 49 Commercial Motor Vehicle Idling Regulation
In July 2004, CARB initially adopted an Airborne Toxic Control Measure (ATCM) to limit idling of diesel-fueled commercial motor vehicles (idling ATCM) and subsequently amended it in October 2005, October 2009, and December 2013. This ATCM is set forth in Title 13, California Code of Regulations, Section 2485, and requires, among other things, that drivers of diesel-fueled commercial motor vehicles with gross vehicle weight ratings greater than 10,000 pounds, including buses and sleeper berth equipped trucks, not idle the vehicle’s primary diesel engine longer than five minutes at any location. This anti-idling regulation helps to reduce fuel consumption by reducing engine usage. The ATCM also requires owners and motor carriers that own or dispatch these vehicles to ensure compliance with the ATCM requirements. The regulation consists of new engine and in-use truck requirements and emission performance requirements for technologies used as alternatives to idling the truck’s main engine. Under the new engine requirements, 2008 and newer model year heavy-duty diesel engines need to be equipped with a non-programmable engine shutdown system that automatically shuts down the engine after five minutes of idling or optionally meet a stringent oxides of nitrogen idling emission standard.

In-Use Off-Road Diesel-Fueled Fleets Regulation
In May 2008, CARB approved the In-Use Off-Road Diesel-Fueled Fleets Regulation (Off-Road Regulation), which was later amended in December 2009, July 2010, December 2011, and November 2022. The overall purpose of the Off-Road Regulation is to reduce emissions of oxides of nitrogen and particulate matter from off-road diesel vehicles operating within 48 USEPA. 2024. EPA Grants Waiver for California’s Advanced Clean Cars II Regulations. December 18. Available at: https://www.epa.gov/newsreleases/epa-grants-waiver-californias-advanced-clean-cars-ii-regulations.

Accessed: October 2025.
49 CARB. CARB Chair Liane Randolph responds to illegal and unconstitutional approval of Congressional Review Act resolutions by the U. S. Senate. Available at: https://ww2.arb.ca.gov/news/carb-chair-liane-randolph-respondsillegal-and-unconstitutional-approval-congressional-review. Accessed: October 2025.

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14 Energy Environmental and Regulatory Overview Ramboll California. The regulation applies to all self-propelled off-road diesel vehicles 25 horsepower or greater used in California and most two-engine vehicles. The Off Road Regulation:
• Imposes limits on idling (i.e., fleets must limit unnecessary idling to 5 minutes), requires a written idling policy, and requires a disclosure when selling vehicles; • Requires all vehicles to be reported to CARB (using the Diesel Off-Road Online Reporting System, DOORS) and labeled;
• Restricts the adding of older vehicles into fleets starting on January 1, 2014; and • Requires fleets to reduce their emissions by retiring, replacing, or repowering older engines, or installing Verified Diesel Emission Control Strategies (i.e., exhaust retrofits).

The anti-idling component of this Off-Road Regulation helps to reduce fuel consumption by reducing engine usage.

The latest amendments include the following changes:50
• Phase out of the oldest and highest-emitting off-road engines from operation; • Restrict the addition of vehicles with Tier 3 and Tier 4 Interim engines; • Require contracting entities to obtain and retain a fleet's valid Certificate of Reported Compliance prior to awarding a contract or hiring a fleet; • Mandate the use of R99 or R100 Renewable Diesel for all fleets; • Provide voluntary compliance flexibility options for fleets that adopt zero-emission technology; and
• Provide additional flexibility for permanent low-use vehicles.

Tractor-Trailer Greenhouse Gas Regulation
CARB’s Tractor-Trailer Greenhouse Gas regulation reduces the energy consumption of large trucks. CARB developed this regulation to make heavy-duty tractors more fuel-efficient. Fuel efficiency is improved by requiring the use of aerodynamic tractors and trailers that are also equipped with low rolling resistance tires. The tractors and trailers subject to this regulation must either use USEPA’s SmartWay (SmartWay) certified tractors and trailers or retrofit their existing fleet with SmartWay verified technologies. The SmartWay certification process is part of their broader voluntary program called the SmartWay Transport Partnership Program.

The regulation applies primarily to owners of 53-foot or longer box-type trailers, and owners of the heavy-duty tractors that pull them on California highways. These owners are responsible for replacing or retrofitting their affected vehicles with compliant aerodynamic technologies and low rolling resistance tires. All owners regardless of where their vehicle is registered must comply with the regulation when they operate their affected vehicles on California highways. Besides the owners of these vehicles, drivers, motor carriers, California-based brokers and California-based shippers that operate or use them also share in the responsibility for compliance with the regulation. 50 CARB. 2022. Rulemaking Documents for the In-Use Off-Road Diesel-Fueled Fleets Regulation. Available at:
https://ww2.arb.ca.gov/our-work/programs/use-road-diesel-fueled-fleets-regulation/rulemaking-documents.

Accessed: October 2025.

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15 Energy Environmental and Regulatory Overview Ramboll Zero-Emission Vehicles
ZEVs include hydrogen fuel cell electric vehicles and plug-in electric vehicles, such as battery electric vehicles and plug-in hybrid electric vehicles.

In 2012, Governor Brown issued EO B-16-2012, which calls for the increased penetration of ZEVs into California’s vehicle fleet in order to help California achieve a reduction of GHG emissions from the transportation sector equaling 80 percent less than 1990 levels by 2050.

In furtherance of that state-wide target for the transportation sector, the EO also calls upon CARB, the CEC and the California Public Utilities Commission to establish benchmarks that will:
(1) allow over 1.5 million ZEVs to be on California roadways by 2025, and (2) provide the state’s residents with easy access to ZEV infrastructure. EO B-16-2012 specifically directed California to “encourage the development and success of ZEVs to protect the environment, stimulate economic growth, and improve the quality of life in the state.”51 In 2018, Governor Brown also issued EO B-48-18, which launched an eight-year initiative to accelerate the sales of ZEVs through a mix of rebate programs and infrastructure improvements. The EO also sets a new target of five million ZEVs in California by 2030 and includes funding for multiple state agencies to increase electric vehicle (EV) charging infrastructure and provide purchase rebates/incentives.

In July 2020, CARB prepared an Assessment of CARB’s Zero-Emission Vehicles Programs Per Senate Bill 498. In this report, CARB staff reviews its programs that affect the adoption of light, medium, and heavy-duty ZEVs, including identifying each program’s goals and status in meeting those goals, performing a cost-benefit analysis where data are available, and comparing CARB’s ZEV programs with those of other jurisdictions. Additionally, pursuant to SB 498, CARB provides policy recommendations for increasing the use of ZEVs in the state, as well as recommendations for vehicle fleet operators to increase the use of ZEVs.52 The California Zero-Emission Vehicle Market Development Strategy was published in February 2021.53 This strategy was prepared to meet the targets identified by Governor Newsom in EO N-79-20, which include the following zero-emission vehicle targets for California:
• 100% of in-state sales of new passenger cars and light-duty trucks will be zero-emission by 2035,
• 100% zero-emission medium and heavy-duty vehicles in the state by 2045 where feasible and by 2035 for drayage trucks, and
• 100% zero-emission off-road vehicles and equipment operations by 2035, where feasible.
51 Executive Order B-16-2012. Available at: https://www.ca.gov/archive/gov39/2012/03/23/news17472/.

Accessed: October 2025.
52 CARB. 2020. Assessment of CARB’s Zero-Emission Vehicles Programs Per Senate Bill 498. Available at:
https://ww2.arb.ca.gov/sites/default/files/2024-04/SB%20498%20Final%20Report%20071620_1.pdf.

Accessed: October 2025.
53 CARB. 2021. California Zero-Emission Vehicle Market Development Strategy. Available at:
https://static.business.ca.gov/wp-content/uploads/2021/02/ZEV_Strategy_Feb2021.pdf. Accessed:

October 2025.

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16 Energy Environmental and Regulatory Overview Ramboll A document prioritizing near-term actions for the next year was prepared in August 2021 called the ZEV Pillar Priorities.54 This annual implementation document identifies the near-term actions to create market opportunity, remove barriers, and further collective understanding.

Advanced Clean Trucks
In June 2020, CARB approved the ACT regulation, which has requirements for manufacturer ZEV sales and a one-time reporting requirement for large entities and fleets.55 The Advanced Clean Truck Regulation is part of a holistic approach to accelerate a large-scale transition of zero-emission medium- and heavy-duty vehicles from Class 2b to Class 8. Manufacturers who certify Class 2b-8 chassis or complete vehicles with combustion engines are required to sell zero-emission trucks as an increasing percentage of their annual California sales from 2024 to 2035. By 2035, zero-emission truck/chassis sales need to be 55% of Class 2b – 3 truck sales, 75% of Class 4 – 8 straight truck sales, and 40% of truck tractor sales. Large employers including retailers, manufacturers, brokers, and others are required to report information about shipments and shuttle services. Fleet owners, with 50 or more trucks, are required to report about their existing fleet operations. This information helps to identify future strategies to ensure that fleets purchase available zero-emission trucks and place them in service where suitable to meet their needs. In May 2025, the United States Congress and Senate voted to disapprove California’s Clean Air Act waiver for the ACT regulation.
56 Executive Order N-79-20
On September 23, 2020, California Governor Gavin Newsom issued EO N-79-20, which entails the following actions:
• All new passenger vehicles sold in California be zero-emission by 2035 • All medium- and heavy-duty vehicles be zero-emission where feasible by 2045 • All off-road vehicles and equipment be zero-emission where feasible by 2035 Governor Newsom ordered extensive interagency efforts to support the EO, including evaluations of technological feasibility and cost effectiveness, expansion of EV charging options and affordable fueling, as well as identification of near-term strategies to increase zero-emission public transportation options.

The EO was generally aimed at transitioning away from fossil fuel dependence in the state, with emphasis on transportation initiatives. However, Governor Newsom addressed efforts to repurpose oil production facilities and extraction sites while continuing the state’s existing goals to reduce the carbon intensity of fuels.57
54 CARB. 2021. ZEV Pillar Priorities. Available at: https://static.business.ca.gov/wpcontent/uploads/2021/08/ZEVPillarPriority.pdf. Accessed: October 2025. 55 CARB. 2020. Advanced Clean Trucks. Available at: https://ww2.arb.ca.gov/our-work/programs/advanced-cleantrucks. Accessed: October 2025. 56 CARB. CARB Chair Liane Randolph responds to illegal and unconstitutional approval of Congressional Review Act resolutions by the U. S. Senate. Available at: https://ww2.arb.ca.gov/news/carb-chair-liane-randolph-respondsillegal-and-unconstitutional-approval-congressional-review. Accessed: October 2025. 57 State of California. 2020. Executive Order N-79-20. Available at: https://www.gov.ca.gov/wpcontent/uploads/2020/09/9.23.20-EO-N-79-20-Climate.pdf. Accessed: October 2025.

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17 Energy Environmental and Regulatory Overview Ramboll Advanced Clean Fleets
In October 2022, CARB approved the Advanced Clean Fleets (ACF) regulation, which has requirements for fleets to phase in the use of ZEVs from 2024 to 2042 and beyond. The fleets required to comply with the regulation include state and local government agency fleets, high priority and federal fleets, and drayage fleets. The regulation also includes a requirement for manufacturers to only sell zero-emission trucks starting in 2036. The ACF regulation is meant to complement the ACT regulation and will contribute to meeting the goals set out in Governor Newsom’s EO N-79-20. On January 13, 2025, California withdrew its request for a waiver and authorization for the ACF regulation.58 CARB is not enforcing the existing portions of the ACF regulation that require a federal waiver or authorization. This includes the high priority and drayage fleet portions of the ACF regulation. Note, the state and local government fleets portion of the ACF remains unaffected as it does not require a federal waiver or authorization.32F
59 2.2.3 Local Programs

2.2.3.1 City of Lake Forest General Plan
The City of Lake Forest General Plan, adopted June 2020, has land use and design, mobility, economic development, recreation and resources, public safety, public facilities, and health and wellness elements.60 The Public Facilities chapter of the General Plan includes Goal PF-6:

Energy Management, which includes the following policies aimed to create a community with adequate power, provided through economically and environmentally sustainable means. • PF-6.1: Compliance with State Legislation. Comply with all state requirements regarding the generation of power and encourage energy providers to investigate the use or expansion of renewable sources of energy.
• PF-6.2: New Development. Continue to require new development and redevelopment to provide verification from energy utilities that states they are able to accommodate the additional demand for service.
• PF-6.3: City-Sponsored Projects and Activities. Evaluate renewable energy capacity on municipal property and renewable energy use in City-sponsored projects and activities.
• PF-6.4: Business Community. Support the decisions of the Lake Forest business community as they select and implement the most appropriate, financially feasible, and responsible energy source for their individual operations. • PF-6.5: Conservation. Promote conservation strategies during design, construction, and maintenance of facilities.
58 CARB. 2025. Withdrawal of California’s Request for a Waiver, Pursuant to Clean Air Act Section 209(b), and Request for Authorization, Pursuant to Clean Air Act Section 209(e)(2), for the Advanced Clean Fleets (ACF) Regulation, Docket ID EPA-HQ-OAR-2023-0589. January 13. Available at:
https://www.epa.gov/system/files/documents/2025-01/ca-acf-carb-withdrawal-ltr-2025-1-13.pdf. Accessed:

October 2025.
59 CARB. 2025. Advanced Clean Fleets. Available at:
https://ww2.arb.ca.gov/our-work/programs/advanced-clean-fleets. Accessed: October 2025. 60 City of Lake Forest. 2020. General Plan. June. Available at:
https://www.lakeforestca.gov/departments/community_development/planning/plans_and_standard_guidelines.p hp#undefined. Accessed: October 2025.

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18 Energy Environmental and Regulatory Overview Ramboll • PF-6.6: Public-Private Partnerships. Investigate the opportunity to engage in public-private partnerships on energy efficiency, energy storage, and microgrid development to achieve cost savings, reduce energy use, and improve energy reliability. • PF-6.7: Public Education. Promote public education programs that advocate for reducing energy consumption, and promote renewable sources of energy. • PF-6.8: Innovation. Encourage innovative energy management solutions in new developments.
• PF-6.9: Promote Energy Conservation in Existing Building Stock. Promote energy conservation by residents and businesses in existing structures, through the City’s newsletter, flyers, and website, in close coordination with other agencies and local energy providers, including the South Coast Air Quality Management District (SCAQMD) and Southern California Edison.

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3. SIGNIFICANCE THRESHOLDS
The analysis provided in this report evaluates whether the Project’s energy impacts would be potentially significant. The significance of the Project’s energy is assessed relative to the following questions from Section VI, Energy, of Appendix G of the CEQA Guidelines as stated below.

Threshold 1. Would the Project Result in a Potentially Significant Environmental Impact Due to Wasteful, inefficient, or unnecessary consumption of energy resources, during Project construction or operation?
Threshold 2. Would the Project conflict with or obstruct a state or local plan for renewable energy or energy efficiency?
While no quantitative thresholds related to energy are included in the CEQA Guidelines, Part I of Appendix F of the CEQA Guidelines states as follows:
“The goal of conserving energy implies the wise and efficient use of energy.

The means of achieving this goal include:

1. decreasing overall per capita energy consumption,

2. decreasing reliance on fossil fuels such as coal, natural gas and oil, and

3. increasing reliance on renewable energy resources.”
Appendix F of the CEQA Guidelines states that an Environmental Impact Report should include a discussion of the potential energy impacts of a Project, with particular emphasis on avoiding or reducing inefficient, wasteful, and unnecessary consumption of energy.

For purposes of this analysis, impacts to energy resources will be considered to be significant if the Project would result in the wasteful, inefficient or unnecessary consumption of fuel or energy, and conversely if the Project would not incorporate renewable energy or energy efficiency measures into building design, equipment use, transportation or other Project features.

To determine whether a Project would result in the wasteful, inefficient or unnecessary consumption of fuel or energy, and conversely whether the Project would fail to incorporate renewable energy or energy efficiency measures into building design, equipment use, transportation or other Project features, Appendix F of the CEQA Guidelines identifies six categories of potential energy-related environmental impacts:

1. The Project’s energy requirements and its energy use efficiencies by amount and fuel type for each stage of the Project including construction, operation, maintenance and/or removal. If appropriate the energy intensiveness of materials may be discussed.

2. The effects of the Project on local and regional energy supplies and on requirements for additional capacity.

3. The effects of the Project on peak and base period demands for electricity and other forms of energy.

4. The degree to which the Project complies with existing energy standards.

5. The effects of the Project on energy resources.

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6. The Project’s projected transportation energy use requirements and its overall use of efficient transportation alternatives.

This report, relative to Threshold 1, assesses the Project’s electricity, natural gas, gasoline and diesel fuel consumption during construction and operation by way of the six questions above. This report, relative to Threshold 2, evaluates whether the Project would conflict with applicable plans related to renewable energy and energy efficiency (see Appendix A, Project Evaluation Against State and Local Plans).

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4. METHODOLOGY FOR DEVELOPMENT OF ENERGY

PROJECTIONS
This section describes the methodology that Ramboll used to estimate energy consumption associated with the proposed Project, which includes one-time demand from construction and annual operational demand. This section also summarizes the proposed Project’s energy consumption based on compliance with applicable regulatory requirements.

Additional information regarding methodology can be found in the Greenhouse Gas Technical Report for the proposed Project;
61 only the methodology specific to energy usage is
discussed in this report. California Emissions Estimator Model (CalEEMod®) outputs can be found in the appendices of the GHG Technical Report for the proposed Project.

4.1 Construction Equipment & Activities
Project construction is planned to begin in October 2026 and would continue for 9 months.

Construction of the proposed Project requires the use of transportation fuel, including gasoline, and diesel use in construction equipment, material transport and delivery via vendor/hauling trucks, and construction worker vehicles. Fuel consumed by off-road construction equipment would be the primary energy resource expended over the course of construction, while VMT associated with the transportation of construction materials and construction worker commutes would also result in fuel consumption. Off-road construction equipment associated with construction activities would use diesel fuel. Construction workers would travel to and from the Project site throughout the duration of construction; this analysis assumed that construction workers would primarily use gasoline-powered passenger vehicles.

Off-road construction equipment of various types would be used during each phase of construction. Methodology consistent with CalEEMod was used to estimate construction equipment usage, and results are included in the appendices to the GHG Technical Report for the proposed Project. Fuel consumption from off-road construction equipment was estimated by converting the exhaust carbon dioxide (CO2) emissions from these equipment in each construction phase to gallons of diesel fuel using USEPA’s CO2 emission factor for diesel engines.
62 The estimated diesel fuel usage from off-road construction equipment for construction are shown in Table 4-1.

Fuel consumption from worker, vendor, concrete truck, and hauling trips are estimated by multiplying the trip rate by the trip length to obtain total VMT for each trip type, and then applying the average fuel consumption rate for vehicles used for each trip type to this VMT.

Consistent with CalEEMod defaults, worker vehicles are assumed to include light-duty automobiles and trucks, vendor vehicles are assumed to include an equal mix of medium heavy-duty trucks and heavy heavy-duty trucks, and hauling vehicles are assumed to include heavy heavy-duty trucks. Concrete trucks are assumed to be heavy heavy-duty trucks. Estimated on-road fuel usage for construction is shown in Table 4-2. 61 Ramboll. 2025. Foothill Ranch Costco Project Greenhouse Gas Emissions Technical Report. 62 USEPA. GHG Emission Factors Hub. Available at
https://www.epa.gov/system/files/documents/2025-01/ghg-emission-factors-hub-2025.pdf. Accessed:

October 2025.

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4.2 Operational Energy Requirements
Energy requirements are evaluated for the first year of the proposed Project operations, which would be 2027. The proposed Project’s energy consumption was estimated using CalEEMod default methodologies for non-mobile sources, including building energy use, which is assumed to include both natural gas and electricity consumption.

4.2.1 Electricity
Operation of the proposed Project will result in electricity demand for the warehouse and parking lot. The annual electricity usage for each land use is presented in Table 4-3. The total electricity use for the Project incorporates 2019 Title 24 standards. Please note that the proposed Project would meet or exceed the Title 24 energy efficiency standards in effect at the time of building permit application, therefore it is conservative to use the 2019 Title 24 standards because newer requirements will be more stringent, leading to greater energy reductions. Additionally, the proposed Project will also meet the California Green Building Code requirements which include a number of green building practices to reduce energy use.

The proposed Project includes EV charger commitments involving twelve (12) direct current fast charging (DCFC) stations, two (2) of which will be ADA accessible. Lastly, the Project will install solar panels to generate renewable electricity, which will be stored in on-site solar batteries that will meet the 2022 California Energy Code requirements including the 2024 amendments. This will displace some of the electricity used by the Project.

4.2.2 Natural Gas
Based on CalEEMod default methodologies, operation of the proposed Project will result in natural gas demand for the warehouse. Ramboll utilized CalEEMod default assumptions to calculate the annual natural gas use for the proposed Project’s land uses, which includes natural gas usage from water heating, primary heating, cooking, cooling, refrigeration, and other miscellaneous end uses. The CalEEMod default annual natural gas usage for the warehouse is presented in Table 4-4.

4.2.3 Mobile Source Fuel Usage
The Project-specific fleet mix of the vehicles visiting the Project is shown in Table 4-5.

Gasoline, natural gas, diesel, and electricity consumption for all mobile sources associated with the proposed Project operation are shown in Table 4-6, Table 4-7, Table 4-8, and Table 4-9, respectively. The following mobile sources are associated with the proposed Project operation: customer and employee vehicles visiting the proposed warehouse, warehouse and tire center delivery trucks, and TRUs that are mounted on the trailers of a portion of the warehouse delivery trucks. Refer to Section 4.3.2 of the GHG Technical Report of the proposed Project for a description of the methodology used to develop activity data for these mobile sources. On-road vehicle fuel consumption for the proposed Project operation is calculated by dividing the VMT by each vehicle type with the respective average fuel efficiency of these vehicle types operating in Orange County in calendar year 2027. TRU fuel consumption is calculated based on the hours of TRU operation and the average fuel consumption rate of TRU trailers operating in Orange County in calendar year 2027.

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4.2.4 Landscape Equipment Fuel Usage
The proposed Project will result in gasoline usage from landscape equipment used on-site during Project operation. As shown in Table 4-10, the proposed Project’s landscape equipment fuel consumption was estimated by converting the carbon dioxide (CO2) emissions from these equipment to gallons of gasoline using USEPA’s CO2 emission factor for gasoline engines.63

4.2.5 Stationary Source Fuel Usage
The proposed Project includes one compressed natural gas-powered emergency generator, rated at 95 horsepower, to support warehouse operations. Testing and maintenance of the generator would remain below 200 hours per year64 or 1 hour on any given day. As shown in Table 4-11, the proposed Project’s emergency generator fuel consumption was estimated by converting the exhaust carbon dioxide (CO2) emissions from these emergency generators to kBtu of natural gas using USEPA’s CO2 emission factor for natural gas engines.65 63 USEPA. GHG Emission Factors Hub. Available at:
https://www.epa.gov/system/files/documents/2025-01/ghg-emission-factors-hub-2025.pdf.

Accessed: October 2025.
64 Per SCAQMD Rule 1110.2, emergency standby engines must not operate more than 200 hours a year. 65 USEPA. GHG Emission Factors Hub. Available at: https://www.epa.gov/system/files/documents/2025-01/ghgemission-factors-hub-2025.pdf. Accessed: October 2025.

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5. PROJECT INVENTORY IN CONTEXT
This section discusses the assessment of the proposed Project’s energy demand against the CEQA significance thresholds outlined in Section 3.

5.1 Threshold 1
Would the Project Result in a Potentially Significant Environmental Impact Due to Wasteful, Inefficient, or Unnecessary Consumption of Energy Resources, During Project Construction or Operation?

5.1.1 Energy Requirements and Energy Use Efficiencies
This section addresses the following category of environmental impact described in Appendix F of the CEQA Guidelines:

The Project’s energy requirements and its energy use efficiencies by amount and fuel type for each stage of the Project including construction, operation, maintenance and/or removal. If appropriate the energy intensiveness of materials may be discussed.

5.1.1.1 Construction
Construction of the proposed Project would result in fuel usage as shown in Table 5-1.

There are no unusual Project characteristics or construction processes that would require the use of equipment that would be more energy intensive than is used for comparable activities, or equipment that would not conform to current emissions standards (and related fuel efficiencies).

5.1.1.2 Operations
Operation of the proposed Project would result in electricity, gasoline, natural gas, and diesel fuel usage, as shown in Table 5-2. There are no unusual Project characteristics that would require electricity, gasoline, natural gas, and diesel consumption that would be more energy intensive than is used for comparable activities, or equipment that would not conform to current emissions standards (and related fuel efficiencies).

Over the lifetime of the proposed Project, the fuel efficiency of the vehicles being used for Project operation is expected to improve. The amount of fuel consumption from vehicular trips to and from the Project site during operation would correspondingly decrease over time as vehicles become more efficient. Numerous regulations have been adopted that encourage, and require, increased fuel efficiency. For example, CARB has adopted an approach to passenger vehicles that combines the control of smog-causing pollutants and GHG emissions into a single coordinated package of standards. The approach also includes efforts to support and accelerate the numbers of plug-in hybrids and zero-emissions vehicles in California. As such, operation of the proposed Project is expected to use decreasing amounts of fuel over time, due to advances in fuel economy.

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5.1.2 Local and Regional Energy Supplies
This section addresses the following category of environmental impact described in Appendix F of the CEQA Guidelines:

The effects of the Project on local and regional energy supplies and on requirements for additional capacity.

5.1.2.1 Construction
The proposed Project’s fuel consumption during construction is discussed in Section 4.1.

The off-road construction equipment used during Project construction are primarily diesel-fueled (Table 4-1). Additionally, the fleet mix for construction mobile sources is expected to be gasoline-powered and diesel-powered, based on the CalEEMod default fleet mix for worker, vendor, and hauling vehicles (see Table 4-2 for additional details). Hence, the Project is not expected to use any natural gas during construction.

Relative to total fuel comparison countywide, the proposed Project construction would use up to 0.0001% of gasoline and 0.02% of diesel fuel for 2026, and up to 0.001% of gasoline and up to 0.03% of diesel fuel for 2027 over the duration of construction (Table 5-1). In comparison to the 2026 and 2027 annual state-wide usage projections, construction of the proposed Project would use up to approximately 0.000006% of gasoline and 0.0008% of diesel fuel for 2026, and up to 0.00005% of gasoline and up to 0.001% of diesel fuel for 2027 (Table 5-1). Therefore, fuel use during construction would be temporary and negligible. Fuel consumption was estimated using CalEEMod, which utilizes EMFAC2021 for on-road mobile source emissions, and OFFROAD2021 for off-road mobile source emissions for Orange County.

5.1.2.2 Operations
Electricity
The Project’s electricity demand during operation is discussed in Section 4.2.1 and 4.2.3.

For comparison, based on 2024 consumption, operation of the proposed Project would equate to 0.01% of the total electricity demand countywide and 0.009% of the total electricity demand state-wide (Table 5-2). Therefore, the Project is not expected to have an impact on the local utility.

In 2024, total in-state electricity consumption was 282,783 GWh.66 The CEC estimates that state-wide energy demand will increase to 395,870 GWh in 2040. 67 The proposed Project’s
anticipated electricity usage of 2,065,126 kilowatt hours (kWh)/year is 0.009% of the state-wide demand in 2024. Given that the state is growing annually, the anticipated state-wide energy demand for the proposed Project’s operational buildout year of 2027 will likely be greater than that in 2024, and thus the proposed Project’s relative percentage contribution to the state-wide energy demand would be even less. 66 Data for Orange County and the State of California in 2024 are obtained from the California Energy Commission, Energy Consumption Data Files. Available at: https://www.energy.ca.gov/files/energy-consumption-data-files.

Accessed: October 2025.
67 California Energy Commission. 2024. CEDU 2024 Baseline Forecast – Total State. Available at:
https://efiling.energy.ca.gov/GetDocument.aspx?tn=260931. Accessed: October 2025.

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The proposed Project’s electricity use projections also represent a small percentage of regional estimates for SCE. The CEC estimates that SCE energy demand will increase to about 111,256 GWh in 2027.
68 The proposed Project’s anticipated electricity usage of 2,065,126 kWh/year is approximately 0.002% of the projected SCE planning area demand in 2027.

Overall, the proposed Project’s projected electricity demand is consistent with, and a small percentage of, state and regional projections. Therefore, the Project will not require additional generation capacity beyond the general state-wide expansion.

Natural Gas Usage
As described in Section 4.2.2 and Section 4.2.5, natural gas consumption during Project operation is from both the warehouse operation and emergency generation operation. The proposed Project is also expected to result in a reduction in natural gas consumption resulting from the negative VMT from customer and employee vehicles visiting the warehouse. Based on 2024 consumption, the proposed Project’s anticipated natural gas usage of 1,075,473 kBtu/year would equate to 0.002% of the total natural gas consumption countywide and 0.001% of the total natural gas consumption state-wide (Table 5-2).

Gasoline Usage
The proposed Project’s gasoline usage during operation is discussed in Section 4.2.3 and Section 4.2.4. The proposed Project is expected to result in a reduction in gasoline consumption driven by the negative VMT from customer and employee vehicles visiting the warehouse. The reduction in the gasoline usage as a result of the Project is presented in Table 5-2.

Diesel Usage
The proposed Project’s diesel usage during operation is discussed in Section 4.2.3 and Section 4.2.5. Project operational diesel consumption is approximately 43,637 gallons/year, which is 0.02% of the total diesel that would be used countywide and 0.001% of the total diesel that would be used state-wide in 2027 (Table 5-2).

5.1.2.3 Summary
The proposed Project will not have a substantial impact on the local or regional energy supplies or require additional capacity to be constructed. Hence, the proposed Project’s energy impacts on energy supplies and capacity are less than significant.

5.1.3 Peak and Base Period Demands
This section addresses the following category of environmental impact described in Appendix F of the CEQA Guidelines:

The effects of the Project on peak and base period demands for electricity and other forms of energy.
68 California Energy Commission. 2024. CEDU 2024 Baseline Forecast - SCE. Available at:
https://efiling.energy.ca.gov/GetDocument.aspx?tn=260928. Accessed: October 2025.

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5.1.3.1 Construction
The Project does not include substantial electric-powered equipment. And while some electricity may be used for uses such as a temporary construction trailer, the amount of electricity is expected to be de minimis in the context of effects on peak and base demands due to the limited nature of such electricity usage.

5.1.3.2 Operation
The proposed Project operation will not have a substantial impact on the peak and base period demands for electricity or other forms of energy. The proposed Project’s base energy consumption compared to regional and state-wide energy consumption is discussed above in Section 5.1.2. Further details and reasoning on the peak demand are described below.

In 2024, California’s peak grid demand was 48,232 megawatts (MW). 69 SCE recorded a peak
demand of 24,659 MW in 2022.
70 In comparison, the Project’s maximum demand is expected to be approximately 0.6 MW in 2027. This is a conservative estimate since it was derived by dividing the total electricity energy required for Project operation by the annual number of working hours, though some sources of electricity would operate 24 hours per day for every day of the year. Thus, the proposed Project will have a relatively negligible effect on state-wide and SCE peak demands.

5.1.3.3 Summary
As described above, the Project will not have a substantial impact on peak and base period demands for electricity and other forms of energy. Hence, the proposed Project’s impacts are less than significant.

5.1.4 Existing Energy Standards
This section addresses the following category of environmental impact described in Appendix F of the CEQA Guidelines:

The degree to which the Project complies with existing energy standards.

5.1.4.1 Construction
Project construction requires use of on-road trucks for soil hauling and deliveries, and off-road equipment such as excavators, tractors/loaders/backhoes, forklifts, and graders.

The construction activities would comply with the five-minute idling limit in the Commercial Motor Vehicle Idling Regulation71 and the Off-Road Regulation. 72 Additionally, on-road trucks
69 California ISO. California ISO Peak Load History 1998 through 2024. Available at:
https://www.caiso.com/documents/californiaisopeakloadhistory.pdf. Accessed: October 2025. 70 California Energy Commission. 2022. Peak Electricity Demand. Available at:
https://efiling.energy.ca.gov/GetDocument.aspx?tn=248075&DocumentContentId=82389. Accessed: October 2025.
71 13 CCR 2485: Airborne Toxic Control Measure to Limit Diesel-Fueled Commercial Motor Vehicle Idling.

Available at: https://www.law.cornell.edu/regulations/california/13-CCR-2485. Accessed: October 2025. 72 CARB. Frequently Asked Questions: Regulation for In-Use Off-Road Diesel-Fueled Fleets. Available at:
https://ww2.arb.ca.gov/sites/default/files/classic/msprog/ordiesel/faq/idlepolicyfaq.pdf. Accessed: October 2025.

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used during Project construction would be compliant with the requirements of the Tractor-Trailer Greenhouse Gas Regulation.73

5.1.4.2 Operation
The proposed Project’s anticipated operational energy use is discussed in Section 4.2. There are no unusual Project characteristics that would require the use of gasoline, diesel, natural gas, or electricity that would be more energy intensive than is used for comparable activities, equipment, or vehicles that would not conform to current emissions standards (and related fuel efficiencies). Additionally, the proposed Project would meet or exceed the Title 24 energy efficiency standards in effect at the time of building permit application. The proposed Project will include pre-manufactured metal wall panels with insulation which carry a higher R-Value and greater solar reflectivity to help conserve energy as compared to other materials. Building heat absorption is further reduced by a decrease in the thermal mass of the metal wall when compared to a typical masonry block wall. Furthermore, the proposed Project will be located in a central location and will serve local customers efficiently, which would result in less transportation energy consumption compared to warehouse locations further away from the populations they serve. Any passenger vehicles and trucks trips generated by the proposed Project would comply with existing and new state-wide vehicle efficiency regulations, discussed further in Section 5.1.6. Furthermore, the proposed delivery trucks accessing the site would comply with the state’s Commercial Motor Vehicle Idling Regulation, similar to the construction vehicles discussed above. Additional detail on the proposed Project’s compliance with existing State and local energy standards and policies is provided in Appendix A.

5.1.4.3 Summary
As described above, the proposed Project will comply with all applicable energy standards and its impacts are less than significant.

5.1.5 Energy Resources
This section addresses the following category of environmental impact described in Appendix F of the CEQA Guidelines:

The effects of the Project on energy resources.

The proposed Project’s energy use is discussed in Section 4 above, including electricity, gasoline, natural gas, and diesel consumption associated with on-site equipment, mobile operations, and construction activities. The proposed Project’s use of energy will not have a substantial effect on state-wide or regional energy resources. Total operational energy use requirements for the proposed Project are summarized in Table 5-2. Programs and measures relevant to energy resources are discussed in detail above.

The proposed Project will not significantly impact energy resources and its impacts are less than significant.
73 CARB. Tractor-Trailer Greenhouse Gas Regulation. Available here: https://ww2.arb.ca.gov/ourwork/programs/ttghg-regulation/regulatory-and-guidance-documents. Accessed: October 2025.

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5.1.6 Transportation Energy Use
This section addresses the following category of environmental impact described in Appendix F of the CEQA Guidelines:

The Project’s projected transportation energy use requirements and its overall use of efficient transportation alternatives.

Conventional gasoline and diesel vehicles consume gasoline or diesel fuel, whereas EVs consume electricity that can be sourced by fossil fuels or renewables. EVs, including battery-electric vehicles and plug-in hybrid electric vehicles, comprise a growing fraction of the passenger vehicles on the roads in California. EV adoption is expected to increase over the upcoming decades due in part to improvements in battery technology and public initiatives and goals. This increase in EV adoption will decrease the fuel requirements due to transportation.

Gasoline and diesel fuel usage for the Project is expected to decrease over time as fleets become more fuel-efficient and switch to more electric-powered vehicles.

5.1.7 Summary
Based on the above analysis of each of the environmental impact factors identified in CEQA Guidelines Appendix F, the potential for the proposed Project to result in wasteful, inefficient, or unnecessary consumption of fuel or energy, and conversely to fail to incorporate energy efficiency measures into equipment use, transportation or other Project features is less than significant.

5.2 Threshold 2
Would the Project Conflict with or Obstruct a State or Local Plan for Renewable Energy or Energy Efficiency?
The proposed Project would comply with any applicable local and State plans, regulations, and policies for renewable energy or energy efficiency to the extent required by law. The proposed Project will include the installation of on-site solar panels, which will generate onsite renewable energy for the Project. Additionally, the proposed Project would not conflict with the goals set forth in the energy efficiency objectives in the City of Lake Forest General Plan (Section 2.2.3.1).
74 The Project’s evaluation against the plan is provided in Table A-1 of Appendix A and discussed in Section 5.1.4.2. Additionally, the Project does not conflict with State regulations and policies as shown in the evaluation presented in Table A-2 in Appendix A. As such, Project impacts are less than significant. 74 City of Lake Forest. 2020. General Plan. June. Available at:
https://www.lakeforestca.gov/departments/community_development/planning/plans_and_standard_guidelines.p hp#undefined. Accessed: October 2025.

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TABLES
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Table 4-1. Off-Road Equipment Fuel Consumption During Construction Foothill Ranch Costco Project
Lake Forest, California
Construction Phase Name
CO2 Emissions 1
(MT/yr)
Diesel Consumption 2
(gallons/yr)
Demolition (2026) 74.6 7,307
Site Preparation (2026) 28.8 2,824
Grading (2026) 48.7 4,774
Grading (2027) 148.8 14,573
Building Construction3
(2027) 146.8 14,377
Paving (2027) 12.3 1,208
Architectural Coating (2027) 2.3 225
Constants:

10.21 kg CO2/gallon diesel consumed in combustion engines 4 1,000 kg CO2/MT CO2
Notes:

Abbreviations:

CalEEMod® - CALifornia Emissions Estimator MODel
CO2 - carbon dioxide
GHG - greenhouse gas
kg - kilograms
MT - metric ton
USEPA - United States Environmental Protection Agency
yr - year
1 Exhaust CO2 emissions from off-road construction equipment used during the Demolition; Site Preparation; Grading; Building Construction; Concrete Pour; Paving; and Architectural Coating construction phases that occur during Project construction are obtained from the CalEEMod® model run shown in Appendix A of the Costco Foothill Ranch Greenhouse Gas Emissions Technical Report.
2 Diesel consumption of off-road construction equipment during each construction phase is estimated as a ratio of the CO2 emissions from these equipment to the CO2 emission factor per gallon of diesel consumed.
4 Obtained from the USEPA GHG Emission Factors Hub. Available at:
https://www.epa.gov/system/files/documents/2025-01/ghg-emission-factors-hub-2025.pdf.

Accessed: August 2025.
3 The concrete pour activity occurs during building construction and is included in this phase.

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Table 4-2. On-Road Vehicle Fuel Consumption During Construction Foothill Ranch Costco ProjectLake Forest, California
Phase
Duration 1
(days)
Worker Trip
Rates 2
(one-way
trips/day)
Vendor Trip
Rates 2,3
(one-way
trips/day)
Hauling Trip
Rates 2
(one-way
trips/day)
Worker Trip
Length 4
(miles/oneway trip)
Vendor Trip
Length 3,4
(miles/one-way
trip)
Hauling Trip
Length 4
(miles/one-way
trip)
Worker Vehicle
Miles Traveled 5
(miles)
Vendor Vehicle
Miles Traveled 5
(miles)
Hauling Vehicle
Miles Traveled 5
(miles)
Worker
Gasoline Fuel
Consumption 6
(gallons)
Vendor Diesel Fuel
Consumption 6,7
(gallons)
Hauling Diesel Fuel
Consumption 6
(gallons)
48 15.0 - 121.3 18.5 - 20 13,320 - 116,480 491 - 18,97212 17.5 - - 18.5 - - 3,885 - - 143 - -16 20.0 - 50.8 18.5 - 20 5,920 - 16,242 218 - 2,64650 20.0 - 50.8 18.5 - 20 18,500 - 50,758 671 - 8,162 135 52.8 27.1 - 18.5 10.2 - 131,924 37,255 - 4,782 6,542 -102 - 8.2 - - 10.2 - - 8,552 - - 1,720 - 18 15.0 - - 18.5 - - 4,995 - - 181 - -38 21.1 - - 18.5 - - 14,854 - - 538 - - Constants:

10.21 kg CO2/gallon diesel consumed in combustion engines91,000 kg CO2/MT CO2 Notes:Abbreviations: Fuel Consumption Rates by Vehicle Type: 9CalEEMod® - CALifornia Emissions Estimator MODel LDA - light-duty automobile Worker Vehicles in 2026: 0.0369 gallons/mile CO2 - carbon dioxide LDT - light-duty truck Worker Vehicles in 2027: 0.0363 gallons/mile EMFAC - EMission FACtors model MHDT - medium heavy-duty trucks Vendor Vehicles in 2026: 0.1771 gallons/mileGHG - greenhouse gas MT - metric ton Vendor Vehicles in 2027: 0.1756 gallons/mileHHDT - heavy heavy-duty trucks USEPA - United States Environmental Protection Agency Haul Trucks in 2026: 0.1629 gallons/milekg - kilogram Haul Trucks in 2027: 0.1608 gallons/mile Construction Phase
Name 1
Concrete Pour 7, 8 (2027)Grading(2026)
3 Project construction will include concrete pours during the Building Construction phase. For the purposes of this analysis, these concrete trucks are modeled as heavy-heavy duty vendor truck trips in CalEEMod ®. The one-way trip length for the concrete truck trips is assumed to be the CalEEMod® default one-way trip length for vendor trips.

Site Preparation(2026)Demolition(2026)Building Construction(2027)Grading(2027) 8 Fuel consumption rates for on-road vehicles are calculated using vehicle class-specific fuel consumption data from EMFAC2021 (see the supporting table below, which presents EMFAC2021 outputs for 2026 and 2027 in Orange-South Coast), the fleet mix for each trip type (worker, vendor, and hauling), and vehicle miles traveled. The fleet mix for the worker, vendor, and hauling trucks are based on CalEEMod defaults. Worker vehicles are assumed to be gasoline fueled and include light duty automobiles and trucks (25% LDA, 50% LDT1, 25% LDT2). Vendor vehicles are assumed to be diesel fueled and include heavy heavy-duty trucks and medium heavy duty trucks (50% HHDT and 50% MHDT). Hauling vehicles are assumed to be diesel fueled and include heavy heavy-duty trucks (100% HHDT). 1 Construction phases and duration are based on Project-specific information. Refer to Section 4 in the Costco Foothill Ranch Greenhouse Gas Emissions Technical Report for further details.2 The number of worker and vendor trips represent CalEEMod® defaults based on the construction equipment used in each construction phase. The number of hauling trips were estimated by CalEEMod ® based on volume of soil that would be imported/exported during construction and the amount of demolition debris generated. Refer to Section 4 of the Costco Foothill Ranch Greenhouse Gas Emissions Technical Report. 4 The trip lengths for on-road vehicles used during construction are CalEEMod® default values.5 Estimated based on trip rates, trip length, and phase duration. 6 Fuel consumption of on-road vehicles used during each construction phase are estimated as a product of the vehicle miles traveled by each vehicle type and its fuel consumption rate in gallons per mile.

Paving(2027)Architectural Coating (2027)
7 The concrete pour activity occurs during building construction. The concrete truck activity includes both on-road travel and idling activity. Refer to Table B-2 in the Costco Foothill Ranch Greenhouse Gas Emissions Technical Report for further details. 9 Obtained from the USEPA GHG Emission Factors Hub. Available at: https://www.epa.gov/system/files/documents/2025-01/ghg-emission-factors-hub-2025.pdf. Accessed: December 2025.

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Table 4-2. On-Road Vehicle Fuel Consumption During Construction Foothill Ranch Costco ProjectLake Forest, California
Calendar
Year
EMFAC
Vehicle
Class Fuel Type
2026 LDA Gasoline2026 LDT1 Gasoline2026 LDT2 Gasoline2026 MHDT Gasoline2026 HHDT Diesel2027 LDA Gasoline2027 LDT1 Gasoline2027 LDT2 Gasoline2027 MHDT Gasoline2027 HHDT Diesel Abbreviations:

EMFAC - EMission FACtors modelHHDT - heavy heavy-duty trucksLDA - light-duty automobileLDT - light-duty truckMHDT - medium heavy-duty trucksVMT - vehicle miles traveled 69,266
1,295,979 211,088
361,927
1,309,094
65,465
842,379126,436
1,296,155
343,883
22,020,145
3,351,769
41,402,174
EMFAC VMT Output
(miles)

0.16080.19040.03830.03770.03130.16290.19140.03900.03830.0319 Average Fuel Consumption
(gallons/mile)
210,519
21,784,157
3,392,265
41,577,927
EMFAC Fuel Use Output
(gallons)
849,832130,030
Supporting Table of EMFAC Outputs
1,326,241

1040
Table 4-3. Operational Electricity Consumption
Foothill Ranch Costco Project
Lake Forest, California
Project Land Use
Project Electricity Demand 1
(kWh/yr)
Discount Club 1,621,213
Parking Lot 476,600
Total 2,097,813
Notes:

Abbreviations:

CalEEMod® - CALifornia Emissions Estimator MODel
kWh - kilowatt hours
yr - year
1 Obtained from CalEEMod® output for the proposed Project, shown in Appendix A of the Costco Foothill Ranch Greenhouse Gas Emissions Technical Report.

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Table 4-4. Operational Natural Gas Consumption
Foothill Ranch Costco Project
Lake Forest, California
Project Land Use
Project Natural Gas Demand 1
(kBTU/yr)
Discount Club 988,265
Parking Lot 0
Total 988,265
Notes:

Abbreviations:

CalEEMod® - CALifornia Emissions Estimator MODel
kBTU - kilo British Thermal Unit
yr - year
1 Obtained from CalEEMod® output for the proposed Project, shown in Appendix A of the Costco Foothill Ranch Greenhouse Gas Emissions Technical Report.

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Table 4-5. Operational Mobile Source Fleet Mixes
Foothill Ranch Costco Project
Lake Forest, California
Gasoline 41,402,174 43.67% --
Plug-in Hybrid 1,693,689 1.79% --
Electricity 4,089,427 4.31% --
Diesel 72,324 0.08% --
Gasoline 3,351,769 3.98% --
Plug-in Hybrid 17,553 0.02% --
Electricity 21,261 0.03% --
Diesel 181 0.00% --
Gasoline 22,020,145 23.13% --
Plug-in Hybrid 311,544 0.33% --
Electricity 224,425 0.24% --
Diesel 88,904 0.09% --
Gasoline 12,751,503 13.98% --
Plug-in Hybrid 186,464 0.20% --
Electricity 237,228 0.26% --
Diesel 174,319 0.19% --
Gasoline 1,647,637 1.69% --
Diesel 995,052 1.02% --
Electricity 91,019 0.09% --
Gasoline 244,223 0.26% --
Diesel 433,595 0.46% --
Electricity 22,491 0.02% --
Gasoline 343,883 0.35% --
Diesel 1,162,783 1.17% --
Electricity 35,495 0.04% --
Natural Gas 13,849 0.01% --
Gasoline -- -- --
Diesel 1,309,094 -- 100%
Electricity -- -- --
Natural Gas -- -- --
Gasoline -- -- --
Diesel -- -- --
Electricity -- -- --
Natural Gas -- -- --
Gasoline -- -- --
Diesel -- -- --
Electricity -- -- --
Natural Gas -- -- --
MCY Gasoline 2.2% 2.2% 334,154 2.24% --
Gasoline -- -- --
Diesel -- -- --
Electricity -- -- --
Natural Gas -- -- --
Gasoline 54,533 0.24% --
Diesel 29,338 0.13% --
Abbreviations:

CalEEMod® - CALifornia Emissions Estimator MODel MDV - medium-duty vehicle EMFAC - EMission FACtors model MH - motor homes
HHDT - Heavy heavy-duty truck MHDT - medium heavy-duty trucks LDA - light duty automobiles OBUS - other buses
LDT - light-duty trucks SBUS - school buses
LHDT - light heavy-duty trucks UBUS - urban buses
MCY - motorcycles VMT - vehicle miles traveled
3 Default EMFAC2021 output for the Orange County subarea in calendar year 2027. 4 The project specific fleet mix for customer and employee vehicles is estimated by apportioning the fleet mix for vehicles visiting the warehouse into the Projectspecific fuel types (gasoline, plug-in hybrid, electricity, diesel) within each EMFAC vehicle class for vehicles visiting the warehouse (LDA, LDT1, LDT2, MDV, LHDT1, LHDT2, MHDT, MCY, and MH) using the default EMFAC VMT output for those fuel types. 5 The EMFAC vehicle class that represents delivery trucks is HHDT.

MH 0.4% 0.4%
Notes:
1 CalEEMod® default for Orange County, calendar year 2027. 2 Estimated using the CalEEMod® default fleet mix for Orange County. EMFAC vehicle classes that represent vehicles visiting the warehouse include LDA, LDT1, LDT2, MDV, LHDT1, LHDT2, MHDT, MCY, and MH.

UBUS 0.04% --
SBUS 0.1% --
HHDT 0.6% --
OBUS 0.1% --
LHDT2 0.7% 0.7%
MHDT 1.6% 1.6%
MDV 14.5% 14.6%
LHDT1 2.8% 2.8%
LDT1 4.0% 4.0%
LDT2 23.6% 23.8%
EMFAC VMT Output3
(miles/day)
Customer and
Employee Vehicles4
Delivery Truck
Fleet Mix5
LDA 49.5% 49.8%
Fleet Mix for Vehicles
Visiting the Warehouse2
Vehicle
Category Fuel Type
CalEEMod® Default
Fleet Mix1

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Table 4-6. Operational Mobile Source Gasoline Consumption Foothill Ranch Costco ProjectLake Forest, California
Mobile Source Cate
gor
y
Mobile Source Activity 1
(miles/
yr)
Mobile Source Activity Associated
with Gasoline Combustion 2
(miles/
yr)
Gasoline
Consumption 3
(gallons/
yr)
Customer and Employee Vehicles - Gasoline -1,547,904 -1,547,904 -58,033Customer and Employee Vehicles - Plug in Hybrid -40,442 -18,448 -644Constants:Average fuel efficiency of gasoline vehicles in 2027 4 27 miles per gallon Average fuel efficiency of plug-in hybrid electric vehicles in 2027 4 29 miles per gallonNotes:

Abbreviations:CalEEMod
® - CALifornia Emissions Estimator MODel SC - South Coast EMFAC - EMission FACtors model yr - year
1 The total vehicle miles traveled per year were obtained from the CalEEMod ® model run shown in Appendix A of the Costco Foothill Ranch Greenhouse Gas Emissions Technical Report. The value was apportioned into gasoline and plug-in-hybrid vehicle technology categories based on the Orange (SC) sub-area fleet mix for vehicles visiting the warehouse shown in Table 4-5. 2 The vehicle miles traveled by vehicles that is associated with gasoline combustion for each vehicle technology category was estimated based on EMFAC default assumptions for gasoline and plug-in hybrid vehicles operating in Orange (SC) sub-area in calendar year 2027. 3 Gasoline consumption of vehicles are estimated as a ratio of the vehicle miles traveled associated with gasoline combustion for each vehicle technology category and its average fuel efficiency in miles per gallon. 4 The average fuel efficiency for each gasoline vehicle technology category operating in for Orange (SC) sub-area in calendar year 2027 is obtained from EMFAC2021.

1044
Table 4-7. Operational Mobile Source Natural Gas Consumption Foothill Ranch Costco ProjectLake Forest, California
Mobile Source Cate
gor
y
Mobile Source Activity 1
(miles/
yr)
Natural Gas Consumption 2
(kBtu/
yr)
Customer and Employee Vehicles - Natural Gas -241 -4,092Constants:Average fuel efficiency of natural gas vehicles in 2027 3 8.52 miles per diesel equivalent gallon Standard Cubic Feet/Diesel Gallon Equivalent Calculation4 139.3 cubic foot per diesel equivalent gallon Conversion factor5 1.039 kBtu per cubic footNotes:

Abbreviations:CalEEMod
® - CALifornia Emissions Estimator MODel SC - South Coast Btu - British thermal unit U.S. - United StatesEMFAC - EMission FACtors model yr - yearkBtu - kilo-British thermal unit 1 Mobile source activity associated with natural gas combustion was calculated using the total vehicle miles traveled per year, obtained from the CalEEMod
® model run shown in Appendix A of the Costco Foothill Ranch Greenhouse Gas Emissions Technical Report, apportioned into natural gas vehicle categories based on the Orange (SC) sub-area fleet mix for vehicles visiting the warehouse shown in Table 4-5. 2 Natural gas consumption for natural gas vehicles is estimated as a ratio of vehicle miles traveled to the average fuel efficiency of natural gas vehicles in miles per gallon.
4 Obtained from the Alternative Fuels Data Center Gasoline and Diesel Gallon Equivalency Methodology. Available at:
https://afdc.energy.gov/fuels/equivalency-methodology. Accessed: August 2025. 3 The average fuel efficiency for natural gas vehicles operating in Orange (SC) sub-area in calendar year 2027 is obtained from EMFAC2021. 5 Obtained from the NRG Energy Conversion Calculator. Available at: https://www.nrg.com/resources/energy-tools/energy-conversioncalculator.html. Accessed: August 2025.

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Table 4-8. Operational Mobile Source Diesel Consumption Foothill Ranch Costco ProjectLake Forest, California
Mobile Source Category Mobile Source Activity 1
Diesel Consumption 2
(gallons/yr)
Customer and Employee Vehicles - Diesel -54,186 miles per year -3,930Transportation Refrigeration Units 4,145 hours per year 2,890Delivery Trucks 277,817 miles per year 44,676Constants:

Average fuel efficiency of diesel vehicles in 2027 3 13.79 miles per gallon TRU fuel consumption rate 4 0.70 gallons per hour
Average fuel efficiency of diesel trucks in 2027 5 6.22 miles per gallonNotes:

Abbreviations:CalEEMod
® - CALifornia Emissions Estimator MODel
EMFAC - EMission FACtors modelSC - South CoastTRU - transportation refrigeration unityr - year 1 Mobile source activity associated with diesel-fuel combustion was calculated using the total vehicle miles traveled per year, obtained from the CalEEMod
® model run shown in Appendix A of the Costco Foothill Ranch Greenhouse Gas Emissions Technical Report, apportioned into diesel vehicle categories based on the Orange (SC) sub-area fleet mix for vehicles visiting the warehouse shown in Table 4-5. 2 Diesel consumption for TRUs is estimated as a product of the TRU activity and its fuel consumption rate in gallons per hour. Diesel consumption for delivery trucks is estimated as a ratio of vehicle miles traveled to the average fuel efficiency of diesel trucks in miles per gallon. Diesel consumption for diesel customer and employee vehicles is estimated as a ratio of vehicle miles traveled to the average fuel efficiency of diesel vehicles in miles per gallon. 3 The average fuel efficiency for diesel vehicles operating in Orange (SC) sub-area in calendar year 2027 is obtained from EMFAC2021.4 Fuel consumption rate for TRUs on trailers operating in Orange (SC) sub-area in calendar year 2027 is obtained from OFFROAD2021.5 The average fuel efficiency for diesel trucks operating in Orange (SC) sub-area in calendar year 2027 is obtained from EMFAC2021.

1046
Table 4-9. Operational Mobile Source Electricity Consumption Foothill Ranch Costco ProjectLake Forest, California
Mobile Source Category
Mobile Source Activity 1,2
(miles/yr)
Mobile Source Activity Associated with
Electricity Consumption 2
(electric miles/yr)
Electricity Consumption 3
(kWh/yr)
Customer and Employee Vehicles - Electric -86,233 -86,233 -26,045Customer and Employee Vehicles - Plug in Hybrid -40,442 -21,994 -6,643Constants:

Average fuel efficiency for plug-in hybrid electric vehicles in 2027 4 3.31 miles per kWh Average fuel efficiency for electric vehicles in 2027 5 2.53 miles per kWhNotes:

Abbreviations:CalEEMod
® - CALifornia Emissions Estimator MODel SC - South Coast EMFAC - EMission FACtors model yr - yearkWh - kilowatt-hour 5 The average fuel efficiency for electric vehicles operating in Orange (SC) sub-area in calendar year 2027 is obtained from EMFAC2021.4 The average fuel efficiency for plug-in hybrid vehicles operating in Orange (SC) sub-area in calendar year 2027 is obtained from EMFAC2021.2 The fraction of electric vehicle miles traveled by vehicles was estimated based on EMFAC default assumptions for electric and plug-in hybrid vehicles operating in Orange (SC) sub-area in calendar year 2027.
3 Electricity consumption of vehicles are estimated as a ratio of the electric miles traveled for each vehicle technology category and its average fuel efficiency in miles per kWh.
1 Mobile source activity associated with electric vehicles was calculated using the total vehicle miles traveled per year, obtained from the CalEEMod® model run shown in Appendix A of the Costco Foothill Ranch Greenhouse Gas Emissions Technical Report, apportioned into electric vehicle categories based on the Orange (SC) subarea fleet mix for vehicles visiting the warehouse shown in Table 4-5.

1047
Table 4-10. Operational Landscape Equipment Gasoline Consumption Foothill Ranch Costco ProjectLake Forest, California
Area Source Cate
gor
y
CO2 Emissions 1
(MT/
yr)
Gasoline Consumption 2
(gallons/
yr)
Landscape equipment 3.35 381Constants:

8.78 kg CO2/gallon gasoline consumed in combustion engines 3 1,000 kg CO2/MT CO2
Notes:Abbreviations:CalEEMod
® - CALifornia Emissions Estimator MODel
CO2 - carbon dioxide
GHG - greenhouse gaskg - kilogramsMT - metric tonUSEPA - United States Environmental Protection Agencyyr - year 1 Exhaust CO2 emissions from landscaping equipment are obtained from the CalEEMod ® model run shown in Appendix A
in the Costco Foothill Ranch Greenhouse Gas Emissions Technical Report. 2 Gasoline consumption of landscaping equipment is estimated as a ratio of the CO2 emissions from these equipment to the CO2 emission factor per gallon of gasoline consumed. 3 Obtained from the USEPA GHG Emission Factors Hub. Available at:
https://www.epa.gov/system/files/documents/2025-01/ghg-emission-factors-hub-2025.pdf. Accessed: August 2025.

1048
Table 4-11. Operational Emergency Generator Natural Gas Consumption Foothill Ranch Costco Project
Lake Forest, California
Stationary Source Category
CO2 Emissions 1
(MT/yr)
NG Consumption 2
(kBtu/yr)
Emergency Generator 4.84 91,301
Conversions:

53.06 kg CO2/MMBtu natural gas consumed in combustion engines 3 1000 kBtu/MMBtu
1,000 kg CO2/MT CO2
Notes:

Abbreviations:

CalEEMod® - CALifornia Emissions Estimator MODel
CO2 - carbon dioxide
GHG - greenhouse gas
kBTU - thousand British Thermal Unit
kg - kilograms
MMBtu - million British Thermal Units
MT - metric ton
NG - Natural Gas
USEPA - United States Environmental Protection Agency
yr - year
1 Exhaust CO2 emissions from emergency generators are obtained from the CalEEMod® model run shown in Appendix A of the Costco Foothill Ranch Greenhouse Gas Emissions Technical Report. 2 Natural gas consumption of emergency generators is estimated as a ratio of the CO2 emissions from these generators to the CO2 emission factor per MMBtu of natural gas consumed. 3 Obtained from the USEPA GHG Emission Factors Hub. Available at:
https://www.epa.gov/system/files/documents/2025-01/ghg-emission-factors-hub-2025.pdf. Accessed:

September 2025.

Item: 11
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Table 5-1. Energy Resource Summary for Project Construction Foothill Ranch Costco ProjectLake Forest, California
Energy
Resource Year
Project
Construction
Energy
Consumption 1
(gallons)
Orange County
Annual
Consumption 2
(gallons)
Project Construction
Contribution to Orange
County Annual Consumption
(%)
California
Annual
Consumption 2
(gallons)
Project Construction
Contribution to
California Annual
Consumption
(%)
Gasoline 2026 853 1,123,161,101 0.0001% 13,896,130,020 0.000006% Diesel 2026 36,523 175,840,601 0.02% 4,329,988,630 0.0008% Gasoline 2027 6,173 1,102,433,345 0.001% 13,625,442,497 0.00005% Diesel 2027 46,807 175,943,536 0.03% 4,312,788,687 0.001% Notes:

Abbreviations:EMFAC - CALifornia Air Resources Board Emissions Factor MODel% - percent1 Estimated as a sum of the fuel consumption of the off-road construction equipment (Table 4-1) and on-road vehicles (Table 4-2) used during construction of the proposed Project.
2 Fuel consumption data for Orange County and the State of California are obtained from EMFAC2021 and OFFROAD2021 for calendar years 2026 and 2027.

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Table 5-2. Energy Resource Summary for Project Operation Foothill Ranch Costco ProjectLake Forest, California
Energy Resource
Project Operation Energy
Consumption 1
Orange County
Annual Consumption 2,3,4
Project Operation Contribution to
Orange County Annual Consumption
(%)
California
Annual Consumption 2,3,4
Project Operation Contribution to
California Annual Consumption
(%)
Electricity (kWh/yr) 2,065,126 19,225,145,140 0.01% 23,162,309,928 0.009%Natural Gas (kBtu/yr) 1,075,473 56,160,224,134 0.002% 171,762,772,006 0.001%Gasoline (gallons/yr) -58,296 1,102,433,345 -0.01% 13,625,442,497 -0.0004%Diesel (gallons/yr) 43,637 175,943,536 0.02% 4,312,788,687 0.001%Conversions:
1,000,000 kWh/GWh
99,976.1 Btu/therm
1,000 Btu/kBtu
Notes:

Abbreviations:Btu - British thermal unit kBtu - kilo-British thermal unit % - percentEMFAC - EMission FACtors model kWh - kilowatt hours yr - yearGWh - gigawatt hours1 Estimated as a sum of the fuel consumption of Project operational sources listed in Tables 4-3, 4-4, 4-6 through 4-11.4 Natural gas consumption data for Orange County and the State of California are obtained from https://www.energy.ca.gov/files/energy-consumption-data-files for calendar year 2024 as that was the most recent data available. Accessed: August 2025.
2 Diesel and gasoline consumption data for Orange County and the State of California are obtained from EMFAC2021 and OFFROAD2021 for calendar year 2027.3 Electricity consumption data for Orange County and the State of California are obtained from https://www.energy.ca.gov/files/energy-consumption-data-files for calendar year 2024 as that was the most recent data available. Accessed: August 2025.

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DRAFT Costco Foothill Ranch Project
Energy Technical Report
Lake Forest, California
Ramboll

APPENDIX A

PROJECT EVALUATION AGAINST STATE AND LOCAL PLANS
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DRAFT Costco Foothill Ranch Project
Energy Technical Report
Lake Forest, California
Ramboll
List of Tables
Table A-1: Project Evaluation Against Applicable City of Lake Forest General Plan Energy Efficiency Strategies
Table A-2: Project Evaluation Against Applicable State Renewable Energy and Energy Efficiency Strategies
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Table A-1. Project Evaluation Against Applicable City of Lake Forest General Plan Energy Efficiency Strategies Costco Foothill Ranch
Lake Forest, California
# Policy Does it Conflict?
PF-6.1
Compliance with State Legislation. Comply with all state requirements regarding the generation of power and encourage energy providers to investigate the use or expansion of renewable sources of energy.

Does Not Conflict. The Project would comply with all state requirements regarding the generation of power. The electricity for the operation of the Project would be supplied by Southern California Edison (SCE), which is required by the California Renewables Portfolio Standard program to meet the following retail sales milestones for the power it delivers to customers:
• By 2020 - 33 percent of power from RPS-eligible resources • By 2024 - 44 percent of power from RPS-eligible resources • By 2027 - 52 percent of power from RPS-eligible resources • By 2030 - 60 percent of power from RPS-eligible resources Additionally, the Project will install solar panels which will generate renewable electricity and will displace some of the electricity used by the Project.

PF-6.2
New Development. Continue to require new development and redevelopment to provide verification from energy utilities that states they are able to accommodate the additional demand for service.

PF-6.3
City-Sponsored Projects and Activities. Evaluate renewable energy capacity on municipal property and renewable energy use in City-sponsored projects and activities.

PF-6.4
Business Community. Support the decisions of the Lake
Forest business community as they select and implement the most appropriate, financially feasible, and responsible energy source for their individual operations.

Does Not Conflict. As listed below, the Project will include a number of energy conservation strategies during design, construction, and maintenance:
• Parking lot light standards would be designed in order to provide even light distribution, and utilize less energy compared to a greater number of fixtures at lower heights. The use of LED lamps can provide a higher level of perceived brightness with less energy than other lamps such as high-pressure sodium. • New and renewable building materials would typically be extracted and manufactured within the region. • The use of pre-manufactured building components, including structural framing and metal panels, would help minimize waste during construction. • Pre-manufactured metal wall panels with insulation carry a higher R-Value and greater solar reflectivity to help conserve energy as compared to other materials. Building heat absorption would be further reduced by a decrease in the thermal mass of the metal wall when compared to a typical masonry block wall. • The Project would use a reflective cool roof material to produce lower heat absorption and thereby lower energy requirements during the hot summer month. This roofing material would meet the requirements for the USEPA's Energy Star energy efficiency program. • The irrigation system proposes to include the use of deep root watering bubblers for parking lot trees to minimize usage and ensure that water goes directly to the intended planting areas. • The Project would include storm water management plans designed to maintain quality control and storm water discharge rates. • The Project would use native species vegetation and drip irrigation systems, which can greatly reduce potable water consumption. • High-efficiency restroom fixtures would be installed. • Commissioning of mechanical systems would occur to ensure that the HVAC systems are performing as designed. HVAC comfort systems would be controlled by a computerized building management system to maximize efficiency.
• HVAC units planned for the Project are high-efficiency direct ducted units, which have phased out the use of hydrochlorofluorocarbons completely. • Parking lot and exterior lights would be controlled by a centrally controlled Energy Management system. • Lighting would be controlled by the overall project energy management system. • High-efficiency light source and ballasts (LED) and bi-level switching for flourscent fixtures would be used. • Energy efficient Transformers would be used.
• Variable speed motors would be used on make-up air units and booster pumps. • Gas water heaters would be direct vent and 94 percent efficient or greater. • The main building structure would be a pre-engineered system that uses 100 percent recycled steel materials and is designed to minimize the amount of material utilized. • Roof material would be recycled standing seam metal panel, designed for maximum efficiency spanning the structure. • When masonry and concrete are used, the materials purchased would be local to the project, thereby minimizing transportation and impact to local road networks. • Construction waste would be recycled wherever possible. • Floor sealant would be No-VOC and would represent over 80 percent of the floor area. • CO2 would be monitored throughout the warehouse.
• An extensive recycling and reuse program would be implemented for warehouse and office space, including tires, cardboard, grease, plastics, and electronic waste. • The use of plastic shopping bags would be avoided.
• Suppliers would be required to reduce packaging and to consider alternative packaging solutions. • Distribution facilities would be strategically located to minimize miles traveled for delivery. Deliveries would be made in full trucks. • All Costco trucks would be equipped with an engine idle shut off timer.

PF-6 Policies
Does Not Conflict. This is an action that the City would implement rather than an individual project. However, the Project would not conflict with the City's ability to implement this measure.

Additionally, it has been verified that additional energy demand of the Project can be accommodated by local energy utilities.

Conservation. Promote conservation strategies during design, construction, and maintenance of facilities. PF-6.5

Item: 11
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# Policy Does it Conflict?
PF-6.6
Public-Private Partnerships. Investigate the opportunity to engage in public-private partnerships on energy efficiency, energy storage, and microgrid development to achieve cost savings, reduce energy use, and improve energy reliability.

PF-6.7
Public Education. Promote public education programs that advocate for reducing energy consumption, and promote
renewable sources of energy.

PF-6.8 Innovation. Encourage innovative energy management solutions in new developments.

PF-6.9
Promote Energy Conservation in Existing Building Stock.

Promote energy conservation by residents and businesses in existing structures, through the City’s newsletter, flyers, and website, in close coordination with other agencies and local energy providers, including the SCAQMD and Southern
California Edison.
# Action Does it Conflict?
PF-6a Confer with utility providers regarding major development plans and participate in the planning of the extension of utilities. Not Applicable. This is an action that the City would implement rather than an individual project. However, the Project would not conflict with the City's ability to implement this measure.

PF-6b
Continue to review development projects to ensure that all new public and private development complies with the California Code of Regulations, Title 24 standards as well as the energy efficiency standards established by the General Plan and the Municipal Code.

Does Not Conflict. The Project would meet or exceed the Title 24 energy efficiency standards in effect at the time of building permit application. These features are listed above. Furthermore, the proposed Project will comply with the CalGreen Building Standards Code that is in effect at the time of the building permit application, as applicable.

PF-6c
Develop a public education program to increase public
participation in energy conservation, including information on programs that provide free or low-cost energy efficiency audits and retrofits to existing buildings.

PF-6d Cooperate with other agencies, jurisdictions, and organizations to expand energy conservation programs.

PF-6e
Support SCE and other private partners to promote widespread marketing through the City’s newsletter, flyers, and website to encourage conservation and greater energy efficiency in homes and businesses.

PF-6f
Promote the CEC Building Energy Benchmarking Program (AB 802) on the City’s website to help benchmark and monitor energy use for participating businesses seeking to increase energy efficiency and realize cost savings.

PF-6g
Educate City residents via the City’s newsletter, flyers, website, and at community events about appliance and equipment
incentives and rebates offered by utility providers, the CEC, and the South Coast Air Quality Management District.

PF-6h
Support SCE by promoting the energy and cost saving benefits of solar hot water heating systems for businesses and residents in the City through the City website, newsletter, and handouts.

PF-6i
Support SCE by promoting residential retrofit programs through the City’s newsletter, flyers, and website to help homeowners convert to all electrical appliances and HVAC systems, consistent with the goals established in SCE’s Pathway 2045 efforts.

Not Applicable. This is an action that the City would implement rather than an individual project. However, the Project would not conflict with the City's ability to implement this measure.

Additionally, the Project will install solar panels which will generate renewable electricity and will displace some of the electricity used by the Project.

Not Applicable. This is an action that the City would implement rather than an individual project, however the Project would not conflict with the City's ability to implement this measure. Additionally, the Project would implement a number of energy-saving project design features, which would result in the Project meeting or exceeding the Title 24 energy efficiency standards in effect at the time of building permit application. These features are listed above.

Does Not Conflict. The Project will include design features that exceed the Title 24 energy efficiency standards in effect at the time of building permit application. These features are listed above.

Additionally, the Project would include solar panels which would provide renewable energy to the Project.

Table A-1. Project Evaluation Against Applicable City of Lake Forest General Plan Energy Efficiency Strategies Costco Foothill Ranch
Lake Forest, California
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# Action Does it Conflict?
PF-6j
Promote, via the City’s website and materials for residents and businesses, participation in SCE’s Green Rate program, which allows residential and business electricity customers to pay low monthly fees to meet electricity needs from either 50 percent or 100 percent renewable sources.

PF-6k
Provide a related flyer at the public counter and strongly encourage new development projects to install electrified space (HVAC) and water heating systems in lieu of natural gas systems, above and beyond the requirements of Title 24 (2019 version), consistent with the strategies identified in SCE’s Pathway 2045, before and during the building plan check process.

Notes:

Abbreviations:

AB - Assembly Bill RPS - Renewables Portfolio Standard
CEC - California Energy Commission SCAQMD - South Coast Air Quality Management District CO2 - carbon dioxide SCE - Southern California Edison
HVAC - heating, ventilation, and air conditioning USEPA - United States Environmental Protection Agency PF - Public Facilities VOC - volatile organic compounds 1 Applicable policies and actions for Goal PF-6: Energy Management were referenced from the City of Lake Forest General Plan, adopted June 2020. Available at:
https://www.lakeforestca.gov/departments/community_development/planning/plans_and_standard_guidelines.php#undefined. Accessed: September 2025.

Not Applicable. This is an action that the City would implement rather than an individual project, however the Project would not conflict with the City's ability to implement this measure. Additionally, the Project would implement a number of energy-saving project design features, which would result in the Project meeting or exceeding the Title 24 energy efficiency standards in effect at the time of building permit application. These features are listed above.

Table A-1. Project Evaluation Against Applicable City of Lake Forest General Plan Energy Efficiency Strategies Costco Foothill Ranch
Lake Forest, California
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Table A-2. Project Evaluation Against Applicable State Renewable Energy and Energy Efficiency Strategies Costco Foothill RanchLake Forest, California
# Plan Category Description Does it Conflict?
1 California Renewables Portfolio Standard (RPS) and SB 100 As most recently amended by SB 100 (2018), California’s RPS increases the proportion of electricity from renewable sources to 33 percent renewable power by 2020; 50 percent renewable power by 2026; and, 60 percent renewable power by 2030. SB 350 (2015) also requires the State Energy Resources Conservation and Development Commission to double (by 2030) the energy efficiency savings in electricity and natural gas final end uses of retail customers through energy efficiency and conservation.

Does Not Conflict. The Project would not conflict with implementation of the state's RPS. The electricity for the operation of the Project would be supplied by Southern California Edison (SCE), which is required by the California Renewables Portfolio Standard program to meet the following retail sales milestones for the power it delivers to customers:• By 2020 - 33 percent of power from RPS-eligible resources• By 2024 - 44 percent of power from RPS-eligible resources• By 2027 - 52 percent of power from RPS-eligible resources• By 2030 - 60 percent of power from RPS-eligible resources Additionally, the Project will install solar panels which will generate renewable electricity and will displace some of the electricity used by the Project. 3 Assembly Bill 1109
The Lighting Efficiency And Toxics Reduction Act (AB 1109) requires a reduction in average statewide electrical energy consumption by not less than 50 percent from the 2007 levels for indoor residential lighting and not less than 25 percent from the 2007 levels for indoor commercial and outdoor lighting by 2018.

Does Not Conflict. The Project would not conflict with the implementation of AB 1109. Additionally, the proposed Project will incorporate several sustainability and energy efficiency measures including green building practices as required by the Title 24 energy efficiency standards in effect at the time of building permit application. These are listed in Table A-1.Does Not Conflict. The Project would meet or exceed the Title 24 energy efficiency standards in effect at the time of building permit application. As noted in Table A-1 and listed below, the Project will include a number of energy and water efficiency features:• Parking lot light standards would be designed in order to provide even light distribution, and utilize less energy compared to a greater number of fixtures at lower heights. The use of LED lamps can provide a higher level of perceived brightness with less energy than other lamps such as high-pressure sodium.• New and renewable building materials would typically be extracted and manufactured within the region.• The use of pre-manufactured building components, including structural framing and metal panels, would help minimize waste during construction. • Pre-manufactured metal wall panels with insulation carry a higher R-Value and greater solar reflectivity to help conserve energy as compared to other materials. Building heat absorption would be further reduced by a decrease in the thermal mass of the metal wall when compared to a typical masonry block wall. • The Project would use a reflective cool roof material to produce lower heat absorption and thereby lower energy requirements during the hot summer month. This roofing material would meet the requirements for the USEPA's Energy Star energy efficiency program. • The irrigation system proposes to include the use of deep root watering bubblers for parking lot trees to minimize usage and ensure that water goes directly to the intended planting areas.• The Project would include storm water management plans designed to maintain quality control and storm water discharge rates.• The Project would use native species vegetation and drip irrigation systems, which can greatly reduce potable water consumption. • High-efficiency restroom fixtures would be installed. • Commissioning of mechanical systems would occur to ensure that the HVAC systems are performing as designed. HVAC comfort systems would be controlled by a computerized building management system to maximize efficiency.• HVAC units planned for the Project are high-efficiency direct ducted units, which have phased out the use of hydrochlorofluorocarbons completely. • Parking lot and exterior lights would be controlled by a centrally controlled Energy Management system.• Lighting would be controlled by the overall project energy management system. • High-efficiency light source and ballasts (LED) and bi-level switching for fluorescent fixtures would be used. • Energy efficient Transformers would be used.
• Variable speed motors would be used on make-up air units and booster pumps. • Gas water heaters would be direct vent and 94 percent efficient or greater.• The main building structure would be a pre-engineered system that uses 100 percent recycled steel materials and is designed to minimize the amount of material utilized. • Roof material would be recycled standing seam metal panel, designed for maximum efficiency spanning the structure. • When masonry and concrete are used, the materials purchased would be local to the project, thereby minimizing transportation and impact to local road networks. • Construction waste would be recycled wherever possible. • Floor sealant would be No-VOC and would represent over 80 percent of the floor area. • CO2 would be monitored throughout the warehouse.
• An extensive recycling and reuse program would be implemented for warehouse and office space, including tires, cardboard, grease, plastics, and electronic waste.• The use of plastic shopping bags would be avoided.• Suppliers would be required to reduce packaging and to consider alternative packaging solutions. • Distribution facilities would be strategically located to minimize miles traveled for delivery. Deliveries would be made in full trucks. • All Costco trucks would be equipped with an engine idle shut off timer.

Title 24, Part 6 of the California Code of Regulations establishes energy and water efficiency requirements for residential and non-residential new construction, additions to existing buildings, and alterations to existing buildings. Standards include requirements for water heating, HVAC, lighting, electrical systems, and solar design.

California Code of Regulations, Title 24, Part 6
2

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# Plan Category Description Does it Conflict?
4 California Green (CalGreen) Building Standards Code Requirements CalGreen establishes green building standards to meet the goals of AB 32. CalGreen includes standards for residential and nonresidential structures such as new buildings or portions of new buildings, additions and alterations, and all occupancies where no other state agency has the authority to adopt green building standards applicable to those occupancies. Standards include requirements for site development, indoor and outdoor water use, construction waste reduction, disposal and recycling and building maintenance and operation.

Does Not Conflict. The Project will comply with the CalGreen Building Standards Code that is in effect at the time of the building permit application, as applicable.

Furthermore, the proposed Project will include several sustainability and energy efficiency measures, including those mandated by California Green Building Standards Code. For a detailed list of these measures, please refer to Table A-1. 5 AB 1493 (Pavley Regulations)
Reduces GHG emissions in new passenger vehicles from model years 2012-2016 (Phase I) and model years 2017–2025 (Phase II). Also reduces gasoline consumption to a rate of 31 percent of 1990 gasoline consumption (and associated GHG emissions) by 2020.

Does Not Conflict. The Project would not conflict with the implementation of the AB 1493 regulations. 6 Low Carbon Fuel Standard (LCFS) Establishes protocols for measuring and reducing the life-cycle carbon intensity of transportation fuels and helps to establish use of alternative fuels. Does Not Conflict. The Project would not conflict with implementation of the LCFS. 7 Advanced Clean Cars (ACC) Program
In 2012, the California Air Resources Board (CARB) adopted the ACC program to reduce criteria pollutant emissions and GHG emissions for model year vehicles 2015 through 2025. ACC includes the Low-Emission Vehicle (LEV) regulations that reduce criteria pollutants and GHG emissions from light- and medium-duty vehicles, and the Zero-Emission Vehicle (ZEV) regulations that require manufacturers to produce an increasing number of pure ZEVs (meaning battery electric and fuel cell electric vehicles), with provisions to also produce plug-in hybrid electric vehicles (PHEV) in the 2018 through 2025 model years. In 2022, CARB developed the ACC II regulations which seeks to reduce criteria and greenhouse gas emissions from new light- and medium-duty vehicles beyond the 2025 model year, and increase the number of ZEVs for sale. On December 18, 2024, the USEPA granted a waiver for California’s ACC II regulation.

Does Not Conflict. The Project would not conflict with implementation of the ACC program. The United States Congress and Senate voted to disapprove California’s Clean Air Act waivers for Advanced Clean Cars II using the Congressional Review Act (CRA) in late May 2025. In response to this action, CARB stated that they “will pursue every remedy available to challenge these actions”
8 Advanced Clean Trucks (ACT)
In 2021, the CARB adopted the ACT regulation to accelerate the market for on-road zero-emission vehicles and to reduce emissions of oxides of nitrogen (NOx), fine particulate matter (PM), other criteria pollutants, toxic air contaminants, and GHG from medium- and heavy-duty on-road vehicles. ACT applies to any manufacturer that certifies on-road vehicles over 8,500 lbs. gross vehicle weight rating for sale in California unless specified as exempt.

Does Not Conflict. The Project would not conflict with implementation of the ACT regulation. The United States Congress and Senate voted to disapprove California’s Clean Air Act waivers for Advanced Clean Trucks using the Congressional Review Act (CRA) in late May 2025. In response to this action, CARB stated that they “will pursue every remedy available to challenge these actions”.
9 Advanced Clean Fleets (ACF)
In October 2022, CARB approved the Advanced Clean Fleets (ACF) regulation, which has requirements for fleets to phase in the use of ZEVs from 2024 to 2042 and beyond. The fleets required to comply with the regulation include State and local government agency fleets, high priority and federal fleets, and drayage fleets. The regulation also includes a requirement for manufacturers to only sell zero-emission trucks starting in 2036. The ACF regulation is meant to complement the ACT regulation and will contribute to meeting the goals set out in Governor Newsom’s Executive Order N-79-20.

Does Not Conflict. The Project would not conflict with implementation of the ACF regulation. In January 2025, CARB withdrew its request for authorization of this rule from the USEPA. 10 Transport Refrigeration Unit (TRU) Air Toxic Control Measure (ATCM) CARB adopted the ATCM for TRUs, TRU generator sets, and facilities where TRUs and TRU generator sets operate in 2004 (amendments in 2010, 2011, and 2022) to reduce diesel particulate matter emissions from diesel-powered TRUs and TRU generator sets.

Does Not Conflict. The Project would comply with all applicable requirements of the TRU ATCM. In January 2025, CARB withdrew its request to the USEPA for authorization of parts of this rule that require TRU owners to turnover at least 15 percent of their diesel-fueled truck TRU fleet to ZE TRU by December 31, 2023, and each year thereafter.

Mobile Sources

Table A-2. Project Evaluation Against Applicable State Renewable Energy and Energy Efficiency Strategies Costco Foothill RanchLake Forest, California 1058
# Plan Category Description Does it Conflict?
11 SB 375
SB 375 establishes mechanisms for the development of regional targets for reducing passenger vehicle GHG emissions. Under SB 375, CARB is required, in consultation with the State’s Metropolitan Planning Organizations, to set regional GHG reduction targets for the passenger vehicle and light-duty truck sector for 2020 and 2035.

Does Not Conflict. The Project would not conflict with the implementation of SB 375.

Abbreviations:

AB - Assembly Bill LEV - Low-Emission VehicleACC - Advanced Clean Cars NOX - oxides of nitrogen ACF - Advanced Clean Fleets PHEV - plug-in hybrid electric vehiclesACT - Advanced Clean Trucks PM - Particulate MatterATCM - Air Toxic Control Measure RPS - Renewables Portfolio StandardCARB - California Air Resources Board SB - Senate BillCO2 - carbon dioxide SCE - Southern California Edison CRA - Congressional Review Act TRU - transport refrigeration unitGHG - greenhouse gases USEPA - United States Environmental Protection AgencyHVAC - heating, ventilation, and air conditioning VOC - volatile organic compoundslbs - pounds ZE - zero emissionLCFS - Low Carbon Fuel Standard ZEV - Zero-Emission VehicleLED - light-emitting diode Mobile Sources

Table A-2. Project Evaluation Against Applicable State Renewable Energy and Energy Efficiency Strategies Costco Foothill RanchLake Forest, California 1059
PC Attachment 5.3
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Costco Wholesale Project
CEQA Guidelines 15183 | Environmental Compliance Checklist Appendix D
Appendix D – Geotechnical Study

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25003229.001A/LH25R178197R Page 1 of 1 April 4, 2025
© 2025 Kleinfelder (Revised November 21, 2025)
24411 Ridge Route Dr. Suite 225, Laguna Hills 92653 p | 949.727.4466 f | 949.727.9242 April 4, 2025
(Revised November 21, 2025)
Kleinfelder Project No. 25003229.001A
Costco Wholesale
9 Corporate Park
Irvine, California 92606
Attention: Mr. Michael Okuma
AVP Real Estate Development
SUBJECT: Geotechnical Study (Revised)
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
CW# 24-1218
Dear Mr. Okuma:

Kleinfelder is pleased to present this report summarizing our geotechnical study for the proposed Costco Wholesale Warehouse located at 26602 Towne Centre Drive in Foothill Ranch, California.

The conclusions and recommendations presented in this report are subject to the limitations presented in Section 7.

We appreciate the opportunity to provide geotechnical engineering services to you on this project.

If you have any questions regarding this report or if we can be of further service, please do not hesitate to contact Brian Crystal 949.727.4466, or Andy Franks, Kleinfelder’s Client Account Manager for Costco at 480.650.4905.

Sincerely,

KLEINFELDER
Hector Marquez, PE Brian E. Crystal, PE, GE
Project Engineer Senior Project Manager
Item: 11
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Copyright 2025 Kleinfelder
All Rights Reserved

ONLY THE CLIENT OR ITS DESIGNATED REPRESENTATIVES MAY USE THIS DOCUMENT AND ONLY FOR THE SPECIFIC PROJECT FOR WHICH THIS REPORT WAS PREPARED.
25003229.001A/LH25R178197R Page i of iv April 4, 2025
© 2025 Kleinfelder (Revised November 21, 2025)

GEOTECHNICAL STUDY (REVISED)

PROPOSED COSTCO WHOLESALE WAREHOUSE
26602 TOWNE CENTRE DRIVE

FOOTHILL RANCH, CALIFORNIA
CW# 24-1218
KLEINFELDER PROJECT NO. 25003229.001A
APRIL 4, 2025
(REVISED NOVEMBER 21, 2025)
Item: 11
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25003229.001A/LH25R178197R Page ii of iv April 4, 2025
© 2025 Kleinfelder (Revised November 21, 2025)
A Report Prepared for:

Costco Wholesale
9 Corporate Park
Irvine, California 92606
Attention: Mr. Michael Okuma
AVP Real Estate Development

GEOTECHNICAL STUDY (REVISED)

PROPOSED COSTCO WHOLESALE WAREHOUSE
26602 TOWNE CENTRE DRIVE

FOOTHILL RANCH, CALIFORNIA
CW# 24-1218
Hector Marquez, PE
Project Engineer
Brian E. Crystal, PE, GE
Senior Project Manager

KLEINFELDER
24411 Ridge Route Drive, Suite 225
Laguna Hills, California
Phone: 949.727.4466
Fax: 949.727.9242
April 4, 2025
(Revised November 21, 2025)
Kleinfelder Project No. 25003229.001A
Item: 11
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TABLE OF CONTENTS
Section Page
25003229.001A/LH25R178197R Page iii of iv April 4, 2025 © 2025 Kleinfelder (revised November 21, 2025)
EXECUTIVE SUMMARY ......................................................................................................ES-1 1 INTRODUCTION.............................................................................................................1

1.1 PROJECT DESCRIPTION...................................................................................1

1.2 SCOPE OF SERVICES .......................................................................................2

1.2.1 Task 1 – Background Data Review...........................................................2

1.2.2 Task 2 – Field Exploration ........................................................................2

1.2.3 Task 3 – Laboratory Testing.....................................................................3

1.2.4 Task 4 – Geotechnical Analyses ..............................................................3

1.2.5 Task 5 – Report Preparation.....................................................................3 2 SITE CONDITIONS.........................................................................................................5

2.1 SITE DESCRIPTION ...........................................................................................5 3 GEOLOGY......................................................................................................................6

3.1 GEOLOGIC SETTING .........................................................................................6

3.1.1 Site Geology.............................................................................................6

3.2 SUBSURFACE CONDITIONS .............................................................................6

3.3 GROUNDWATER................................................................................................7

3.4 ASSESSMENT OF POTENTIAL GEOLOGIC HAZARDS ....................................8

3.4.1 Localized Faulting and Seismicity.............................................................8

3.4.2 Landsliding .............................................................................................10

3.4.3 Liquefaction and Seismic Compression..................................................10

3.4.4 Expansive Soils......................................................................................11

3.4.5 Flooding .................................................................................................11

3.4.6 Oil and Gas Fields..................................................................................12

3.4.7 Land Subsidence....................................................................................12 4 GEOTECHNICAL DESIGN RECOMMENDATIONS .....................................................13

4.1 GENERAL..........................................................................................................13

4.2 SEISMIC DESIGN CONSIDERATIONS.............................................................15

4.2.1 2025 CBC Seismic Design Parameters ..................................................15

4.3 FOUNDATIONS.................................................................................................16

4.3.1 General ..................................................................................................16

4.3.2 Shallow Foundations ..............................................................................16

4.3.3 Short Drilled Pile Foundations ................................................................17

4.4 BUILDING SLAB-ON-GRADE............................................................................18

4.5 EXTERIOR FLATWORK....................................................................................19

4.6 SITE DRAINAGE...............................................................................................19

4.7 RETAINING STRUCTURES..............................................................................20

4.8 PAVEMENT SECTIONS....................................................................................22

4.8.1 Costco Pavement Design Parameters....................................................22

4.8.2 Asphalt Concrete Pavement...................................................................23

4.8.3 Asphalt Performance Grade Binder........................................................23

4.8.4 Portland Cement Concrete Pavement ....................................................24

4.8.5 Aggregate Base......................................................................................24

4.8.6 Pavement Maintenance..........................................................................24

4.9 SOIL CORROSIVITY.........................................................................................24

4.10 STORMWATER MANAGEMENT.......................................................................25 Item: 11
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5 CONSTRUCTION RECOMMENDATIONS....................................................................27

5.1 GENERAL..........................................................................................................27

5.2 EARTHWORK ...................................................................................................27

5.2.1 General ..................................................................................................27

5.2.2 Site Preparation......................................................................................27

5.2.3 Foundation Excavations .........................................................................28

5.2.4 Fill Material and Compaction Criteria......................................................29

5.2.5 Shrinkage/Bulking ..................................................................................30

5.2.6 Excavation Characteristics .....................................................................30

5.2.7 Temporary Excavations..........................................................................31

5.2.8 Trench Backfill........................................................................................31

5.3 UNSTABLE SUBGRADE CONDITIONS............................................................32

5.4 TEMPORARY SHORING...................................................................................33

5.4.1 Lateral Pressures ...................................................................................33

5.4.2 Design of Soldier Piles ...........................................................................34

5.4.3 Lagging ..................................................................................................34

5.4.4 Deflection ...............................................................................................35

5.4.5 Monitoring ..............................................................................................35

5.5 EXTERIOR FLATWORK....................................................................................35

5.6 PAVEMENTS.....................................................................................................35

5.6.1 HMA Design ...........................................................................................35

5.6.2 Construction Considerations...................................................................36 6 ADDITIONAL SERVICES .............................................................................................37

6.1 PLANS AND SPECIFICATIONS REVIEW .........................................................37

6.2 CONSTRUCTION OBSERVATION AND TESTING...........................................37 7 LIMITATIONS ...............................................................................................................38 8 REFERENCES..............................................................................................................40 TABLES
1 Summary of Significant Holocene-Active Faults Near the Project Site 2 2022 CBC Seismic Design Parameters
3 Lateral Earth Pressures for Retaining Structures (Granular Backfill) 4 Recommended Minimum Asphalt Concrete Pavement Sections 5 Corrosion Test Results
6 Summary of Infiltration Test Results
7 Structural Fill Placement And Compaction Criteria

FIGURES
1 Site Vicinity Map
2 Exploration Location Map
3 – 6 Cross Section A-A’, B-B’, C-C’, and D-D’

APPENDICES
A Field Explorations
B Laboratory Testing
C Infiltration Test Results
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Geotechnical Investigation Summary Checklist for Costco Wholesale Projects
General Information
Costco Real Estate Main Contact: Michael Okuma
Geotechnical Main Contact: Brian Crystal (949.585.3113) Geotechnical Engineer of Record: Kleinfelder
Project Location: 26602 Towne Centre Drive, Foothill Ranch, CA CW#: 24-1218
Warehouse #: N/A
Report Date: April 4, 2025 (Revised November 21, 2025)
Consultant Project/Document Number: 25003229.001A/LH25R178197R Addendums (List):

Report Purpose: ☐ Preliminary ☐ Draft ☐ Final ☒ Addendum/Revision Yes
No
or
NA
Describe/ Comments Report
Section
Pre-existing Conditions/Information
Developer provided geotechnical report (describe): ☐ ☒
Pre-existing development (describe) ☒ ☐ Existing commercial development 2.1 Foundation type (describe): ☐ ☒
Performance Issues (describe): ☐ ☒
Environmental Issues (describe) ☐ ☒
Site Grading Records (stripping,compaction test
results,field reports, etc.) ☐ ☒
Typical Building Structural Design Criteria
Other (describe): ☒ ☐ New Costco Warehouse 1.1
Building size (describe): ☒ ☐
165,068-square-foot Costco
Wholesale Warehouse 1.1
Typical wall loading
3 kips / foot* (Metal Buildings) ☐ ☒

4.5 kips / foot* (CMU or pre-cast) ☒ ☐ Both CMU and Metal 1.1 Typical column loading
120 kips in non-snow regions ☒ ☐ 1.1
150 kips in snow regions ☐ ☒
Typical canopy loading: 50 kips ☒ ☐ 1.1
Typical floor slab loading
500 pounds per square foot, (psf, total) ☒ ☐ 1.1
250 psf (dead) at rack areas ☒ ☐
150 psf (dead) at non-rack areas ☒ ☐
350 psf (live) ☒ ☐
Paving Design (20 year life)
Heavy Duty paving shall accommodate 30 trucks per
day (Traffic Index of 7.0) ☒ ☐ 4.8
Light Duty paving shall accommodate 6,600 cars per
day (Traffic Index of 5.0) ☒ ☐ 4.8
Performance Grade (PG) binder oil identified for local
climate conditions ☒ ☐ PG 64-10 4.8.3
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Site Grading Conditions/Assumptions
Deviations to Typical Criteria (list/describe): ☐ ☒
Design Finished Floor Elevation (FFE) (describe): ☒ ☐ Elevation 782.22 feet 1.1 Basis for FFE (assumed, per Civil) (describe): ☒ ☐ Preliminary Grading Plan 1.1 Effects of change to assumed FFE (describe): ☐ ☒
Maximum anticipated cuts (describe): ☒ ☐ Less than 2 feet 1.1 Maximum anticipated fills (describe): ☒ ☐ Less than 6 feet 1.1 Cross sections prepared for sites that are not essentially flat ☒ ☐ Figures 3-6
Amount of import/export anticipated (describe): ☐ ☒ 1.1 Frost Depth (describe): ☐ ☒
Retaining walls
Number of walls (describe): ☒ ☐
1 wall proposed on the west
boundary of the site 1.1
Height/Length of walls (describe): ☒ ☐ Up to approx.6 feet-in height 1.1 Wall construction/type (describe): ☐ ☒
Cut/fill transition in pad (describe): ☐ ☒
Offsite Improvements (describe) ☐ ☒
Fieldwork/Results
Costco Due Diligence Design Criteria
Version (describe): ☒ ☐ Version 2022, dated Oct. 28, 2022 1.1 Followed Criteria? ☒ ☐
Deviations to standard investigation (describe): ☐ ☒
Groundwater
Depth (describe): ☒ ☐
Groundwater was not encountered
during our investigation which was
drilled to an approximate depth of
49½ feet bgs.

3.3 Perched ☒ ☐
Perched groundwater should be
expected during and following
periods of rainfall

3.3 Expected seasonal fluctuation (describe): ☐ ☒
Piezometers installed? ☐ ☒
Unusual/Challenging Soils conditions encountered
Moisture-sensitive soils ☐ ☒
Undocumented fill ☒ ☐
Artificial fill associated with
previous grading at the site was
observed at depths ranging from
approximately 4 to 9½ feet bgs.

3.2 Unsuitable soils (require removal) ☒ ☐ Unsuitable fill soils 5.2.2 Wet soils ☐ ☒
Debris ☐ ☒
Bedrock/potential non-rippable conditions ☒ ☐ Capistrano Formation sandstone 5.2.6 Refusal ☐ ☒ 5.2.6
Collapsible soils ☐ ☒
Expansive soils ☐ ☒
Compressible soils ☐ ☒
Liquefaction ☐ ☒
Sinkholes ☐ ☒
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Other (describe): ☐ ☒
Potential Contamination Identified
Soil ☐ ☒
Groundwater ☐ ☒
Restoration of Disturbed Areas
Backfilled with soil ☒ ☐
Borings were backfilled with soil
cuttings 1.2.2
Backfilled with grout ☐ ☒
Other (describe): ☐ ☒
Topsoil samples collected/analyzed ☐ ☒ Developed site
Corrosivity testing performed/addressed ☒ ☐
Highly corrosive potential to ferrous
metals 4.9
Culinary water quality testing performed ☐ ☒
Report
Executive summary ☒ ☐ ES-1
Wet weather construction recommendations ☐ ☒
Pad winterization/pad recommendations ☐ ☒
Frost protection recommendations ☐ ☒
Design Parameters
Fill material parameters provided
Structural fill (below foundations, slabs) ☒ ☐ 5.2.2
Site grading fill (below pavements, flatwork) ☒ ☐ 5.2.2 Select backfill (behind truck dock walls, foundations,
grade beams, etc.) ☒ ☐ 5.2.4
Trench backfill ☒ ☐ 5.2.8
Drainage fill ☐ ☒
Frost resistant fill ☐ ☒
Slab base aggregate ☒ ☐ Aggregate Base Material 4.4
Limits of debris/unsuitable removal provided ☒ ☐ 5.2.2
Over-excavation/recompaction required ☒ ☐ 5.2.2
Depth (describe): ☒ ☐
Soils within 10 feet of the
warehouse pad should be
overexcavated to a depth of at
least 5 feet below existing grade or
3 feet below the bottom of the
footings and floor slabs, whichever
is deeper, and replaced as
structural fill.

5.2.2 Extent (include cross-section diagram) ☐ ☒
Pad subgrade stabilization required (describe): ☐ ☒ Recommendations provided 5.3 Surcharge ☐ ☒
Height (describe): ☐ ☒
Lateral extent (describe): ☐ ☒
Estimated duration (describe): ☐ ☒
Shallow Foundations ☒ ☐
psf allowable soil bearing pressure (describe): ☒ ☐ 3,000 psf 4.3.2 Deep Foundations ☒ ☐ For light poles 4.3.3
Type (describe): ☒ ☐ Drilled piles
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Options and Value Engineering Matrix provided ☐ ☒
Floor Slabs
Unreinforced (>2500 psf) ☒ ☐ 4.4
Reinforced (describe why) ☐ ☒
Subgrade modulus (ksi/in) (describe): ☒ ☐ 150 pci 4.4
Base Material thickness (min 6") (describe): ☒ ☐ 6 inches of AB 4.4 Seismic Conditions
Governing Building Code (IBC, UBC, other) ☒ ☐ 2025 CBC 4.2.1 Geologic Hazard Identified ☒ ☐ 3.4
Proximity to earthquake fault zone(s) ☒ ☐ 3.4.1
Proximity to seismic hazard zone(s) ☐ ☒
Potential for liquefaction ☐ ☒
Potential for lateral spreading ☐ ☒
Potential for seismic settlement ☐ ☒
Potential for slope stability/landslides ☐ ☒
Potential for groundshaking or geologic hazards ☐ ☒
Retaining Walls ☒ ☐ 4.7
Recommended Wall Types ☐ ☒
Recommend Kleinfelder Design ☐ ☒
Lateral earth pressure design values ☒ ☐ 4.7
Active: ☒ ☐ 4.7
At-rest: ☒ ☐ 4.7
Passive: ☒ ☐ 4.7
Seismic: ☒ ☐ 4.7
Backfill material, placement requirements ☒ ☐ 4.7
Drainage requirements and cross-section drawing ☐ ☒
Finger Drains ☐ ☒
Required for frost ☐ ☒
Recommended for long term maintenance and
constructability ☐ ☒
Pavement
Pavement subgrade stabilization required (describe): ☐ ☒ 5.2.2 Costco asphalt mix design specified ☒ ☐ 4.8.3
Heavy and light duty pavement sections specified ☒ ☐ 4.8.2 Alternative pavement sections identified ☒ ☐ PCC pavement 4.8.4 Specification for offsite pavement sections included ☐ ☒ Data Gaps/Unknowns (describe): ☐ ☒
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EXECUTIVE SUMMARY
This report presents the results of Kleinfelder’s geotechnical study for the proposed Costco Wholesale Warehouse (CW# 24-1218) located at 26602 Towne Centre Drive in Foothill Ranch, California. The purpose of our geotechnical study was to evaluate soil and groundwater conditions at the site and provide geotechnical recommendations for project design and construction. We based our study on the Costco Wholesale Development Requirements (CWDRs), Version 2022, dated October 28, 2022.

Kleinfelder understands Costco plans to purchase an approximately 16.28-acre site to construct a new approximately 165,068-square-foot warehouse. The warehouse building will be a singlestory, steel-framed and concrete-masonry-unit structure (30 feet in height). The building surroundings will consist mainly of surface parking with some landscape areas. Parking and drive areas will be paved with either Portland cement concrete or asphalt concrete pavements. A retaining wall up to approximately 6 feet in height is proposed on the west boundary of the site.

Surface elevations interpreted from an ALTA survey (PBLA Surveying, Inc., 2025) provided by the design team indicates that the existing grades vary from a high of approximately 790 feet at the north portion of the site to a low of approximately 775 feet on the south portion of the site.

Based on the preliminary grading plans prepared by Kimley Horn (the project civil engineer), we understand that the finished floor elevation for the building slab will be established at approximately 782.22 feet. Cuts less than 2 feet and fills less than 6 feet are anticipated to achieve the desired site grades.

The proposed Costco site is located southeast of Highway 241 and Alton Parkway at 26602 Towne Centre Drive in Foothill Ranch, California, as shown on Figure 1. The site is currently developed with an existing theatre building, which will be demolished, in the southwest portion of the site surrounded by asphalt surface parking. The existing development is situated on a previously graded pad with 2:1 (horizontal to vertical) descending slope, up to approximately 30 feet in height, on the western portion of the site.

Subsurface conditions at the site were explored by drilling 28 borings. In addition, 4 borehole infiltration tests were performed. A total of 15 borings were advanced in the building area; and 13 borings and 4 infiltration tests were advanced in the parking and drive areas. The borings were drilled using truck-mounted, hollow-stem-auger drilling equipment to depths between approximately 21½ and 49½ feet below the existing ground surface (bgs) in the warehouse Item: 11
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building area, and between approximately 11½ and 26½ feet bgs in the parking and drive areas.

The borehole infiltration tests were drilled to depths of approximately 5 or 10 feet bgs.

The soils encountered within the borings generally consisted of artificial fill overlying sandstone of the Capistrano Formation. Artificial fill associated with previous grading at the site was observed at depths ranging from approximately 4 to 9½ feet bgs. The fill generally consisted of silty to clayey sand with varying amounts of gravel. The deepest fill was observed along the northwest side of the project site. Based on historical topographic maps, the fill may be deepest along the northwest boundary due to a northwest descending slope. Capistrano Formation sandstone was encountered below the fill to the maximum depth explored of approximately 49½ feet bgs. The sandstone was generally highly weathered and excavates as poorly to well graded sand and silty sand.

Groundwater was not encountered in our borings to the maximum depth explored of approximately 49½ feet bgs. Groundwater is not anticipated to be encountered within the depth of influence of the foundations or excavations planned for the proposed improvements.

Based on the results of our field exploration, and observations during this exploration, it is our professional opinion that the proposed project is geotechnically feasible, provided the recommendations presented in the geotechnical report are incorporated into the project design and construction. We identified the following key geotechnical considerations during our study. • The proposed Costco warehouse and retaining wall may be supported on a conventional shallow foundation system. Overexcavation and recompaction of the onsite soils is recommended in the upper fill soils within the warehouse building pad to provide relatively uniform support for the proposed warehouse and other improvements.
• Light poles may be supported on drilled pile foundations. It should be noted that drilling of the pile shafts may require heavy-duty excavation equipment, and possibly rock coring equipment, to excavate through the Capistrano Formation sandstone. • Soils within 10 feet of the warehouse pad (including the entrance canopy, building aprons, utility pads, stairs, ramps, stoops, and the loading dock) should be overexcavated to a depth of at least 5 feet below existing grade or 3 feet below the bottom of the footings and floor slabs, whichever is deeper, and replaced as structural fill. Depending on the condition of the existing fill at the base of the excavation, additional overexcavation may be required. The overexcavated soils can be moisture conditioned and recompacted as structural fill.

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• For pavement, sidewalk, and flatwork areas, we recommend that the exposed subgrade be proof-rolled with heavy construction equipment (e.g. loader or smoothdrum roller) after the area has been stripped of soft earth materials and construction debris to disclose areas of soft and yielding material. Where soft and yielding material is observed, it should be overexcavated and replaced as structural fill. The proof-rolling should extend beyond the proposed improvements a horizontal distance of at least 2 feet, where possible.
• For the retaining wall on the west boundary of the site, soils should be overexcavated to a depth of at least 2 feet below existing grade or 2 feet below the bottom of the footing, whichever is deeper. The overexcavated soils can be moisture conditioned and recompacted as structural fill. The overexcavation should extend beyond the proposed improvements a horizontal distance of at least 2 feet. • Following overexcavation and prior to replacing soils, the exposed subgrade should be proof rolled with at least a 10-ton roller, fully loaded tandem-axle dump truck or water truck. Areas identified as being soft or yielding may require additional compaction or overexcavation, as determined by Kleinfelder. Following proof rolling and any additional overexcavation, the exposed subgrade should be scarified at least 6 to 8 inches, moisture conditioned, and recompacted.
• For earthwork volume estimating purposes, an average shrinkage value of 5 to 10 percent for the upper surficial soils (generally in the upper 5 to 6 feet) may be assumed.

These values are estimates only and exclude losses due to removal of vegetation or debris. Actual shrinkage/bulking factors will depend on the types of earthmoving equipment used and should be determined during grading. We recommend that the civil engineer or the contractor contact a local earthwork contractor to confirm these values prior to finalizing any earthwork estimates.
• Foundation and slab performance depends greatly on proper irrigation and how well runoff water drains from the site. We recommend that landscape planters either not be located adjacent to structures and pavement areas or be isolated and properly drained to area drains such that cycles of wetting and drying do not impact pavements, flatwork, and other structures. Drought resistant plants and minimum watering are recommended for planters, if used. Planters should be built such that water exiting from them will not seep into the foundation areas or beneath slabs and pavement. • Minimum resistivity values of the samples tested indicate that the soil may be highly corrosive to ferrous metals. The concentrations of soluble sulfates indicate that the subsurface soils represent a Class S0 Class S0 exposure to sulfate attack on concrete Item: 11
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in contact with the soil based on ACI 318-14 Table 19.3.1.1. Therefore, in accordance with ACI Building Code 318-19, no special provisions for selection of cement type are required.
• We have assessed the potential for storm water infiltration into the subgrade soils at the subject project site. Four borehole infiltration tests were performed at depths of approximately 5 and 10 feet bgs. Based on the results of our infiltration testing, it is our opinion that the site is not suitable for onsite infiltration. We recommend alternatives to infiltration Best Management Practices (BMPs), such as biofiltration/bio-retention systems (bio-swales and planter boxes), be implemented at the project site.

The findings, conclusions, and recommendations presented in this executive summary should not be relied upon without consulting our geotechnical report for more information. The conclusions and recommendations presented in this report are subject to the limitations presented in Section 7.

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1 INTRODUCTION
This report presents the results of Kleinfelder’s geotechnical study for the proposed Costco Wholesale Warehouse (CW# 24-1218) located at 26602 Towne Centre Drive in Foothill Ranch, California. The location of the project site is presented on Figure 1, Site Vicinity Map. The purpose of our geotechnical study was to evaluate soil and groundwater conditions at the site and provide geotechnical recommendations for project design and construction. The scope of our services was presented in our proposal titled, “Proposal for Geotechnical Study, Proposed Costco Wholesale Warehouse and Fuel Facility, 26602 Towne Centre Drive, Foothill Ranch, California, CW# 24-1218,” dated November 15, 2024. We based our study on the Costco Wholesale Development Requirements (CWDRs), Version 2022, dated October 28, 2022.

This report presents a description of the services performed, a discussion of the geotechnical conditions observed at the site, and recommendations developed from our engineering analyses of field and laboratory data. Individuals using this report should read the limitations presented in Section 7.

1.1 PROJECT DESCRIPTION
Kleinfelder understands Costco plans to purchase an approximately 16.28-acre site to construct a new approximately 165,058-square-foot warehouse. The warehouse building will be a singlestory, steel-framed and concrete-masonry-unit structure (30 feet in height). The building surroundings will consist mainly of surface parking with some landscape areas. Parking and drive areas will be paved with either Portland cement concrete or asphalt concrete pavements. A retaining wall up to approximately 6 feet in height is proposed on the west boundary of the site.

Based on the CWDRs, we understand maximum column loads will be on the order of 120 kips, typical wall loads will be approximately 4.5 kips per lineal foot, canopy column loads will be approximately 50 kips, and the total slab load (dead plus live loads) will be approximately 500 psf.

Surface elevations interpreted from an ALTA survey (PBLA Surveying, Inc., 2025) provided by the design team indicates that the existing grades vary from a high of approximately 790 feet at the north portion of the site to a low of approximately 775 feet on the south portion of the site.

Based on the preliminary grading plans prepared by Kimley Horn (the project civil engineer), we understand that the finished floor elevation for the building slab will be established at approximately 782.22 feet. Cuts less than 2 feet and fills less than 6 feet are anticipated to achieve the desired site grades.

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1.2 SCOPE OF SERVICES
The scope of our geotechnical study consisted of a literature review, subsurface explorations, geotechnical laboratory testing, engineering evaluation and analysis, and preparation of this report. Studies to assess environmental hazards that may affect the soil and groundwater at the site were beyond our geotechnical scope of services. The following paragraphs present a description of our services.

1.2.1 Task 1 – Background Data Review
We reviewed readily available published and unpublished geologic literature in our files and the files of public agencies, including selected publications prepared by the California Geological Survey and the U.S. Geological Survey. We also reviewed readily available seismic and faulting information, including data for designated earthquake fault zones and our in-house database of faulting in the general site vicinity.

1.2.2 Task 2 – Field Exploration
Because the site is developed, our field exploration could not be performed in full accordance with the CWDRs (i.e. could not perform test pits or any field exploration in areas of existing buildings).

Subsurface conditions at the site were explored by drilling 28 borings. In addition, 4 borehole infiltration tests were performed. A total of 15 borings were advanced in the building area; and 13 borings and 4 infiltration tests were advanced in the parking and drive areas. The borings were drilled using truck-mounted, hollow-stem-auger drilling equipment to depths between approximately 21½ and 49½ feet below the existing ground surface (bgs) in the warehouse building area, and between approximately 11½ and 26½ feet bgs in the parking and drive areas.

The borehole infiltration tests were drilled to depths of approximately 5 or 10 feet bgs. The approximate locations of the borings and infiltration tests are presented on Figure 2, Exploration Location Map.

Prior to commencement of the fieldwork, Underground Service Alert (USA) was notified and various geophysical techniques were used at the boring locations to identify potential conflicts with subsurface structures. A Kleinfelder staff professional supervised the field operations and logged the explorations. Selected bulk and drive samples were retrieved, placed in plastic bags, or sealed in sample tubes, and transported to our laboratory for further evaluation. The number of blows necessary to drive a Standard Penetration Test (SPT) sampler or California-type sampler was recorded. Soil descriptions used on the logs result from field observations and data, as well as from laboratory test data. Stratification lines on the logs represent the approximate boundary Item: 11
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between soil and/or rock types, and the actual transition may vary and can be gradual. Appendix A presents a description of the field exploration program, exploration logs, and a legend of terms and symbols used on the logs.

1.2.3 Task 3 – Laboratory Testing
Laboratory testing was performed on representative bulk and relatively undisturbed samples to assist in soil classification and development of engineering parameters for geotechnical design.

Laboratory testing consisted of moisture content, dry unit weight, wash sieve (percent passing No. 200 sieve), sieve & hydrometer analysis, direct shear, Modified Proctor, R-value, and preliminary corrosion testing. Laboratory testing was performed by both Kleinfelder and AP Engineering and Testing, Inc. of Pomona, California. Appendix B presents the results of the laboratory testing performed for this study.

1.2.4 Task 4 – Geotechnical Analyses
We analyzed field and laboratory data relative to the anticipated finished grades, warehouse layout, and structural loads to provide geotechnical recommendations for design and construction.

We evaluated feasible foundation systems, concrete slab support, pavement design, and earthwork. Seismic design parameters in accordance with the 2022 California Building Code (CBC) are also presented.

1.2.5 Task 5 – Report Preparation
This report summarizes the services performed, data acquired, and our findings, conclusions, and geotechnical recommendations for the design and construction of the proposed improvements.

Our report includes the following items:
• Vicinity map (Figure 1) and field exploration location map (Figure 2) showing the approximate boring and infiltration test locations.
• Boring and infiltration test logs (Appendix A).
• Results of laboratory testing (Appendix B).
• Results of infiltration tests (Appendix C).
• Discussion of general site conditions.
• Discussion of general subsurface conditions as encountered during our field exploration. • Discussion of regional and local geology.

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• Recommendations for seismic design parameters in accordance with the 2022 CBC. • Recommendations for foundation design, allowable bearing pressures, embedment depths, and compatibility constraints under various loading conditions. • Anticipated total and differential static settlements. • Recommendations for site preparation, earthwork, temporary slope inclinations, fill placement, and compaction specifications, including the excavation characteristics of subsurface soil deposits and formational materials.
• Recommendations for support of floor slabs and slabs-on-grade. • Recommendations for flexible and rigid pavement structural sections for light- and heavy-duty pavement based on Equivalent Single Axle loading presented in the CWDRs. • Recommendations for design of retaining structures, including active and at-rest lateral earth pressures, passive and frictional resistance, and applicable surcharge loads. • Preliminary evaluation of the corrosion potential of the on-site soils.

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2 SITE CONDITIONS

2.1 SITE DESCRIPTION
The proposed Costco site is located southeast of Highway 241 and Alton Parkway at 26602 Towne Centre Drive in Foothill Ranch, California, as shown on Figure 1. The site is currently developed with an existing theatre building, which will be demolished, in the southwest portion of the site surrounded by asphalt surface parking. The existing development is situated on a previously graded pad with 2:1 (horizontal to vertical) descending slopes, up to approximately 30 feet in height, on the western portion of the site.

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3 GEOLOGY

3.1 GEOLOGIC SETTING
The project site is located in the northern Peninsular Ranges geomorphic province, a province known for its northwest trending valleys and ranges that are subparallel to the San Andreas and related faults (California Geological Survey (CGS), 2002). More specifically the project site lies along the western flanks of the Santa Ana Mountains. The Santa Ana Mountains are composed of a basement complex of middle Mesozoic-age crystalline and semi-crystalline rocks unconformably overlain by late Cretaceous and Cenozoic clastic strata (Schoellhamer et al., 1981) that were uplifted and folded as a result of movement along the Elsinore Fault and Whittier Fault (Morton and Miller, 2006). The site is bounded by southwest-trending canyons and washes that emerge from the western flanks and deposit young alluvial deposits overlying tertiary-aged strata.

3.1.1 Site Geology
The project site is located in the foothills of the Santa Ana Mountains between Borrego Canyon Wash to the northwest and Serrano Creek to the southeast. Between these drainage areas, the Oso member of the tertiary-aged Capistrano Formation is mapped at the ground surface (Morton and Miller, 2006). Quaternary-aged slope wash (Qsw) is mapped along the perimeter of these exposures and Quaternary-aged alluvium (Qal) overlies the Capistrano Formation in the drainage areas. At the site, the Oso Member of the Capistrano Formation, a white to light gray, massive, fine to coarse grained marine sandstone with scattered gravel underlies up to 9½ feet of artificial fill. According to a historical topographic map from 1949 (U.S. Geological Survey, Department of the Interior, 1949), the ground surface elevation across the site originally exceeded ~790 feet, with the exception of the northwest boundary where the ground surface descended to a local drainage at an elevation of 720 to 740 feet, parallel to the site boundary.

Descriptions of the soils encountered in Kleinfelder’s subsurface exploration are presented in the following sections and on the boring logs presented in Appendix A.

3.2 SUBSURFACE CONDITIONS
The soils encountered within the borings generally consisted of artificial fill overlying sandstone of the Capistrano Formation. Artificial fill associated with previous grading at the site was observed at depths ranging from approximately 4 to 9½ feet bgs. The fill generally consisted of Item: 11
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silty to clayey sand with varying amounts of gravel. The deepest fill was observed along the northwest side of the project site. Based on historical topographic maps, the fill may be deepest along the northwest boundary due to a northwest descending slope. Capistrano Formation sandstone was encountered below the fill to the maximum depth explored of approximately 49½ feet bgs. The sandstone was generally highly weathered and excavates as poorly to well graded sand and silty sand.

3.3 GROUNDWATER
Groundwater was not encountered in our borings to the maximum depth explored of approximately 49½ feet bgs. The project site is located within the Southeast Management Area of the Coastal Plain of Orange County Groundwater Basin (Basin 8-1) (OCWD, City of La Habra and IRWD, 2022). This area consists of several small areas southeast of the Orange County Water District Management Area, a portion of which falls within the Irvine Ranch Water District (IRWD) service area. As reported by IRWD, depth to groundwater information is limited to a half dozen production wells, of which only one is active (LF-2). The nearest IRWD well is LF-7, located approximately 1,500 feet to the southwest of the site at an approximate elevation of 832 feet, and showed groundwater at a depth of approximately160 feet below ground surface (El. 672) between 2020 and 2021. Based on a 2024 groundwater report (Montrose Environmental, 2025) for a former Palisades Gas and Wash Station #824 near Portola Parkway and Market Place, depth to groundwater is within approximately 10 to 15 feet of the ground surface (approximate El 802 to 792). Depth to groundwater here may reflect that site’s proximity to local drainages (Borrego Canyon, Serrano Creek) and their tributaries. Based on available groundwater information in the site vicinity and at the site, groundwater is likely to be encountered within approximately 50 to 100 feet of the ground surface. The California Geological Survey does not report a historical high depth to groundwater at the site but reports historical high groundwater of up to 10 feet below ground surface in nearby drainage areas (Pridmore, C.L, 2000).

Groundwater is not anticipated to be encountered within the depth of influence of the foundations or excavations planned for the proposed improvements, however localized zones of perched water, increased soil moisture content and fluctuations of the groundwater level, should be anticipated during and following the rainy season. Irrigation of landscaped areas on or adjacent to the site can also cause a fluctuation of local groundwater levels.

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3.4 ASSESSMENT OF POTENTIAL GEOLOGIC HAZARDS

3.4.1 Localized Faulting and Seismicity
The most significant geologic hazard to the project site is considered to be the potential for moderate to strong seismic shaking that is likely to occur during the design life of the project. The project site is located in the highly seismic southern California region within the influence of several fault systems. Based on CGS Special Publication 42 (CGS, 2018) the site is not located within a State-designated Alquist-Priolo (AP) Earthquake Fault Zone (EFZ). The nearest mapped Earthquake Fault Zone is located approximately 11.4 miles northeast of the site along the Glen Ivy Segment of the Elsinore fault (CGS, 2018).

The CGS defines Holocene-active faults as those demonstrated to have displacement of the Holocene-age ground surface within the past 11,700 years (end of the Holocene geologic era) and are believed to pose the risk of ground rupture. Pre-Holocene faults that have been demonstrated to have no Holocene surface displacement are not regulated for fault hazards under the CGS Earthquake Zoning Act. Faults of undetermined age cannot be classified as Holoceneactive or pre-Holocene active because there is insufficient data to demonstrate activity with respect to the Holocene time period. Active faults without surface expression (buried faults) and other potentially active seismic sources which may be capable of generating earthquakes are not currently zoned by the Act, but they are known to be present in the region (e.g. San Joaquin fault).

The Elsinore fault is a right-lateral strike slip fault, that is approximately 185 miles long. The Glen Ivy (fault) segment of the Elsinore Fault, is the segment of the fault nearest to the project site, is approximately 22 miles long (Cao et al., 2003) and is found between Corona and Lake Elsinore.

The estimated slip rate along the Glen Ivy fault is approximately 5 millimeters/year (Dawson and Weldon, 2013). The surface trace of the Elsinore fault has been mapped by the State and designated as an EFZ (CGS, 2003). The surface trace has been mapped approximately 11.4 miles northeast of the project site and the active fault is capable of generating an earthquake of Mw 6.8 (Cao et al., 2003) that could lead to significant ground shaking at the site.

The San Joaquin Hills Blind Thrust Fault is a southwest-dipping (approximately 23 degrees), lowangle reverse (thrust) fault that is concealed (blind) and does not reach the ground surface. Since it is not exposed at the ground surface and does not present a potential for surface fault rupture it is not zoned under the Alquist-Priolo Act as an EFZ. Its trace, at depth, is approximately 4.2 miles southwest of the project site and is an important fault with respect to geologic hazards.

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in the Newport-Inglewood-Rose Canyon Fault Zone results in uplift of the San Joaquin Hills along the San Joaquin Hills Blind Thrust Fault. Uplift along this fault began in the early Pleistocene and has continued to the present. This fault has a slip rate of 0.2 to 1.0 millimeters/year (Dawson and Weldon, 2013) and is capable of generating a magnitude (Mw) 7.1 earthquake (Petersen et al., 2008). An earthquake occurring along this fault is expected to cause significant ground shaking at the site.

There are several faults within Southern California that are capable of producing large earthquakes. Four major northwest-trending faults divide the Peninsular Ranges province into blocks (Newport-Inglewood-Rose Canyon, Elsinore, San Jacinto and San Andreas). Table 1 below provides the nearest distance to each fault and a listing of some of the seismic parameters (i.e., fault type, slip rate and magnitude) associated with each of the faults.

Table 1
Summary Of Significant Holocene-Active Faults Near the Project Site Fault Name
(segment name)
Approximate
Fault Distance and
Direction from Site
(miles)
Fault Type
Slip
Rate/Year
(mm)
Maximum
Magnitude
(Mmax)
San Joaquin Hills thrust 4.2, southwest Reverse 0.6 7.1 Elsinore (Glen Ivy Fault) 11.4, northeast Right lateral 5 6.9 Elsinore
(all segments combined) 11.4, northeast Right lateral 4.4 7.8 Newport-Inglewood
(Los Angeles Basin) 16.7, west southwest Right lateral strike slip 1 7.1 Newport-Inglewood
Connected alt 1
(all segments combined)

16.7, west southwest Right lateral 1 7.5
San Jacinto
(San Bernardino) 33.9, northeast Right lateral 6 7.1
San Andreas (San
Bernardino Mountains 41.0, northeast Right lateral 19 7.2 Southern San Andreas
(all segments combined) 41.0, northeast Right lateral 34 8.2 Sources:

Dawson, T.E., and R.J. Weldon. 2013. Appendix B – Geologic Slip Rate Data and Geologic Deformation Model in Field, et al., 2013.

Uniform California earthquake rupture forecast, version 3 (UCERF3)—The time-independent model: U.S. Geological Survey (USGS) Open-File Report 2013–1165, and California Geological Survey (CGS) Special Report 228.

All Other data - Petersen, M.D., Frankel, A.D., Harmsen, S.C., Mueller, C.S., Haller, K., Wheeler, R.L., Wesson, R.L., Zeng, Y., Boyd, O.S., Perkins, D.M., Luco, N., Field, E.H., Wills, C.J., and Rukstales, K.S., 2008, Documentation for the 2008 Update of the United States National Seismic Hazard Maps: U.S. Geological Survey (USGS), Open-File Report 2008–1128, 61p.

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3.4.2 Landsliding
A landslide results from the downgradient movement of earth material along a slope or hillside.

Landslides occur on slopes when soil and base material lose strength, typically from an increase in pore-water pressures and the forces of gravity, causes the soil and base material to move down-gradient. Landslides can result from a variety or combination of root causes such as steepness of slope, type of material, water content of slope soils, amount and type of vegetation, and major natural hazards such as earthquakes, volcanic eruptions, wildfires, and floods. Steeper slopes and weaker rocks are the most vulnerable to mass wasting events. Landslides can occur as slow but progressive movements of soil over time or from the rapid deterioration of soil on a slope. They are frequently triggered by intense rainfall or seismic shaking.

A portion of the site is located within State-designated Seismic Hazard Zone for Earthquake Induced-Landslides (CGS, 2001). The California Geological Survey and California Department of Conservation Landslide Inventory (beta) online database (2025) shows the same landslide and describes it as a dormant mature/old/relict rock slide that had failed from near to the northwest.

More specifically, the landslide failed from the northwest boundary of the site into a small tributary to Borrego Canyon Wash. According to historical photographs, grading of the site as early as 1994 levelled the site. No evidence of the landslide remains. No evidence of distress was observed at the time of our investigation. The risk from landslides and other forms of mass wasting is considered low due and lack of significant slopes at the site.

3.4.3 Liquefaction and Seismic Compression
The term liquefaction describes a phenomenon in which saturated, cohesionless soils temporarily lose shear strength (liquefy) due to increased pore water pressures induced by strong, cyclic ground motions during an earthquake. Structures founded on or above potentially liquefiable soils may experience bearing capacity failures due to the temporary loss of foundation support, vertical settlements (both total and differential), and/or undergo lateral spreading. The factors known to influence liquefaction potential include soil type, relative density, grain size, confining pressure, depth to groundwater, and the intensity and duration of the seismic ground shaking. Liquefaction is most prevalent in loose to medium dense, silty, sandy, and gravelly soils below the groundwater table.

The site is not located within a State hazard zone for liquefaction (CGS, 2001). Because of the lack of groundwater and the soil types at the site, the potential for liquefaction is not considered a hazard at the site.

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Seismic compression results from the accumulation of contractive volumetric strains in unsaturated soil during earthquake shaking. Loose to medium dense granular material with no fines or with low plasticity fines are most susceptible to seismic compression. Based on the density and soil composition of the underlying soils, the potential for seismic compression (dynamic dry settlement) is considered to be very low.

3.4.4 Expansive Soils
Expansive soils are characterized by their ability to undergo significant volume changes (shrink or swell) due to variations in moisture content. Changes in soil moisture content can result from precipitation, landscape irrigation, utility leakage, roof drainage, perched groundwater, drought, or other factors, and may result in unacceptable settlement or heave of structures or concrete slabs supported on grade. The surficial soils are generally silty to clayey sands overlying sandstone and do not undergo significant volume changes when exposed to various moisture contents. Accordingly, the expansion potential of the near surface soils is considered low.

3.4.5 Flooding
Flooding occurs as a result of several factors in developed areas. These factors are rainfall rates that exceed an area’s ability to absorb or control the runoff, impounded water retained behind a downstream flood control structure (upstream-inundation), failure of an upstream flood control structure (inundation), and tsunami.

The Flood Insurance Rate Map (FEMA, 2019) prepared by the Federal Emergency Management Agency (FEMA) was reviewed to identify the potential flood hazard for the project. This map indicates the site is within Zone X which is defined as being an area determined to be outside the

0.2-percent-annual-chance-flood. Based on this information, the potential for the project site to be impacted by regional flooding is considered low.

Dam inundation occurs when a dam is breached or there is an uncontrolled release of water that may cause flooding downstream. According to the Division of Safety of Dams online database (Division of Safety of Dams, 2025), the project site is not located within a hazard zone for dam inundation.

The site within not located within a tsunami hazard area and the risk of tsunami inundation is considered low (State of California, 2021). Due to the location of the site inland of sea, elevation of the site, and the State of California’s hazard classification outside the area of tsunami hazard, the hazard due to tsunami is considered very low.

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A seiche is a wave or sloshing of a body of water that is at least partially impounded caused by strong wind or seismic shaking. The site is not located near a body of water capable of generating a seiche during a seismic event.

3.4.6 Oil and Gas Fields
The project site is not located within a mapped petroleum producing field of Southern California and no oil/gas wells are reported within the Project Site (California Department of Conservation, California Geologic Energy Management Division (CalGEM), 2025). Based on information available from CalGEM, three (3) idle oil and gas wells are within approximately 2.5 to 4.5 miles of the site and several plugged core holes and plugged dry holes are within 1.5 to 2.5 miles of the site. Additional undocumented well(s) may be present and buried near the site.

3.4.7 Land Subsidence
Ground subsidence is a gradual settling or sudden sinking of the earth's surface owing to subsurface movement of earth materials. Ground subsidence results from fluid (water or petroleum) extraction from underlying sediments and/or formations, which causes the collapse of pore spaces previously occupied by the removed fluid. The collapse of these pore spaces compacts the underlying formations leading to a gradual drop in ground surface elevation. Ground subsidence is most often found in areas where large volumetric withdrawals of fluids from underground reservoirs has occurred or is ongoing. Ground shaking from tectonic activity can exacerbate the vertical sinking of land in an area over the withdrawal site. Structures and improvements located in subsidence-prone areas are at risk for damage if subsidence were to occur.

The USGS has been tracking subsidence in California since the early 20th century and has developed maps that illustrate areas of recorded subsidence across the state (USGS, 2021). Most of the subsidence has resulted from excessive groundwater pumping for municipal, industrial, and agricultural uses, although oil extraction is also a documented cause. A review of the USGS subsidence interactive online map shows the project site is not documented to be experiencing subsidence.

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4 GEOTECHNICAL DESIGN RECOMMENDATIONS

4.1 GENERAL
Based on the results of our field exploration, laboratory testing, and engineering analyses conducted during this study, it is our professional opinion the proposed project is geotechnically feasible, provided the design and construction recommendations presented in this report are incorporated into the project. We identified the following key geotechnical considerations during our study.
• The proposed Costco warehouse and retaining wall may be supported on a conventional shallow foundation system. Overexcavation and recompaction of the on-site soils is recommended in the upper fill soils within the warehouse building pad to provide relatively uniform support for the proposed warehouse and other improvements. • Light poles may be supported on drilled pile foundations. It should be noted that drilling of the pile shafts may require heavy-duty excavation equipment, and possibly rock coring equipment, to excavate through the Capistrano Formation sandstone. • Soils within 10 feet of the warehouse pad (including the entrance canopy, building aprons, utility pads, stairs, ramps, stoops, and the loading dock) should be overexcavated to a depth of at least 5 feet below existing grade or 3 feet below the bottom of the footings and floor slabs, whichever is deeper, and replaced as structural fill. Depending on the condition of the existing fill at the base of the excavation, additional overexcavation may be required.

The overexcavated soils can be moisture conditioned and recompacted as structural fill. • For pavement, sidewalk, and flatwork areas, we recommend that the exposed subgrade be proof-rolled with heavy construction equipment (e.g. loader or smooth-drum roller) after the area has been stripped of soft earth materials and construction debris to disclose areas of soft and yielding material. Where soft and yielding material is observed, it should be overexcavated and replaced as structural fill. The proof-rolling should extend beyond the proposed improvements a horizontal distance of at least 2 feet, where possible. • For the retaining wall on the west boundary of the site, soils should be overexcavated to a depth of at least 2 feet below existing grade or 2 feet below the bottom of the footing, whichever is deeper. The overexcavated soils can be moisture conditioned and recompacted as structural fill. The overexcavation should extend beyond the proposed improvements a horizontal distance of at least 2 feet.

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• Following overexcavation and prior to replacing soils, the exposed subgrade should be proof rolled with at least a 10-ton roller, fully loaded tandem-axle dump truck or water truck. Areas identified as being soft or yielding may require additional compaction or overexcavation, as determined by Kleinfelder. Following proof rolling and any additional overexcavation, the exposed subgrade should be scarified at least 6 to 8 inches, moisture conditioned, and recompacted.
• For earthwork volume estimating purposes, an average shrinkage value of 5 to 10 percent for the upper fill soils (generally in the upper 5 to 6 feet) may be assumed. These values are estimates only and exclude losses due to removal of vegetation or debris. Actual shrinkage/bulking factors will depend on the types of earthmoving equipment used and should be determined during grading. We recommend that the civil engineer or the contractor contact a local earthwork contractor to confirm these values prior to finalizing any earthwork estimates.
• Foundation and slab performance depends greatly on proper irrigation and how well runoff water drains from the site. We recommend that landscape planters either not be located adjacent to structures and pavement areas or be isolated and properly drained to area drains such that cycles of wetting and drying do not impact pavements, flatwork, and other structures. Drought resistant plants and minimum watering are recommended for planters, if used. Planters should be built such that water exiting from them will not seep into the foundation areas or beneath slabs and pavement.
• Minimum resistivity values of the samples tested indicate that the soil may be highly corrosive to ferrous metals. The concentrations of soluble sulfates indicate that the subsurface soils represent a Class S0 Class S0 exposure to sulfate attack on concrete in contact with the soil based on ACI 318-14 Table 19.3.1.1. Therefore, in accordance with ACI Building Code 318-19, no special provisions for selection of cement type are required. • We have assessed the potential for storm water infiltration into the subgrade soils at the subject project site. Four borehole infiltration tests were performed at depths of approximately 5 and 10 feet bgs. Based on the results of our infiltration testing, it is our opinion that the site is not suitable for onsite infiltration. We recommend alternatives to infiltration Best Management Practices (BMPs), such as bio-filtration/bio-retention systems (bio-swales and planter boxes), be implemented at the project site.

The following opinions, conclusions, and recommendations are based on the properties of the materials encountered in the borings and test pits, the results of the laboratory-testing program, Item: 11
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and our engineering analyses performed, and should be incorporated into project design and construction.

4.2 SEISMIC DESIGN CONSIDERATIONS

4.2.1 2025 CBC Seismic Design Parameters
Site class was determined based on our understanding of the proposed construction, information obtained from the investigation, published geologic literature and maps, and on our interpretation of the 2025 California Building Code (CBC), which refers to the criteria established in ASCE/SEI 7-22. The subsurface encountered within the borings generally consisted of approximately 5 to 10 feet fill overlying sandstone of the Capistrano Formation. Based on the site geology as shown the borings drilled to depths up to approximately 50 feet below grade, it is our opinion that the site is classified as Site Class BC, Soft Rock.

Approximate coordinates for the site are noted below.
• Latitude: 33.6773 °N
• Longitude: 117.6684 °W
Seismic design parameters were developed consistent with the requirements of the 2025 CBC and ASCE/SEI 7-22. The parameters listed in Table 2 are estimated using the ASCE Hazard Tool website (https://ascehazardtool.org) and the requirements of the 2025 CBC and ASCE/SEI 7-22.

Table 2
2025 CBC Seismic Design Parameters
DESIGN PARAMETER RECOMMENDED VALUE ASCE/SEI 7-22

REFERENCE
Site Class BC
Sections 20.2 and 20.3 and
Table 20.2-1
Ss (g) 1.46 Section 11.4.3
S1 (g) 0.45 Section 11.4.3
SMS (g) 1.31 Section 11.4.3
SM1 (g) 0.45 Section 11.4.3
SDS (g) 0.88 Eq. 11.4-1
SD1 (g) 0.30 Eq. 11.4-2
PGAM (g) 0.54 Section 11.8.3
TL (sec) 8 Fig 22-14
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4.3 FOUNDATIONS

4.3.1 General
Based on the results of our field exploration, laboratory testing, and geotechnical analyses, the proposed warehouse building and retaining wall may be supported on conventional shallow spread footing foundations founded on subgrade prepared in accordance with Section 5.2.2. Light poles may be supported on drilled pile foundations. It should be noted that drilling of the pile shafts may require heavy-duty excavation equipment, and possibly rock coring equipment, to excavate through the Capistrano Formation sandstone.

Recommendations for the design and construction of shallow foundations and short drilled pile foundations are presented below.

4.3.2 Shallow Foundations
Allowable Soil Bearing Pressure
Footings may be designed for a net allowable soil bearing pressure of 3,000 pounds per square foot (psf) for dead plus sustained live loads. Footings should be embedded at least 18 inches below the lowest adjacent exterior grade. The footing dimension and reinforcement should be designed by the structural engineer; however, continuous and isolated spread footings should have minimum widths of 18 and 24 inches, respectively. A one-third increase in the above bearing pressure can be used for transient wind or seismic loads.

The proposed retaining wall on the west boundary of the site will be adjacent to an existing descending slope. Per Section 1808.7 of the 2022 CBC, footings adjacent to descending slopes steeper than 3:1 (horizontal:vertical) should be established at a depth such that a horizontal setback distance of at least H/3 is maintained between the slope face and the outer bottom edge of the footing, where H is the overall slope height.

Estimated Settlements
We estimate total static settlement of foundations designed and constructed in accordance with the recommendations presented above to be less than 1 inch. Differential static settlement between similarly loaded footings is estimated to be less than ½ inch over 50 feet.

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Lateral Resistance
Lateral load resistance may be derived from passive resistance along the vertical sides of the footings, friction acting at the base of the footing, or a combination of the two. An allowable passive resistance of 250 psf per foot of depth may be used for design. Allowable passive resistance values should not exceed 2,500 psf. For the proposed retaining wall on the west boundary of the site, an allowable passive resistance of 150 psf per foot of depth may be used for design and should not exceed 1,500 psf. The allowable passive resistance for the retaining wall footings has been reduced for the descending slope condition adjacent to the wall.

An allowable coefficient of friction of 0.35 between the base of the footings and the engineered fill soils can be used for sliding resistance using the dead load normal stresses. Friction and passive resistance may be combined without reduction. We recommend that the first foot of soil cover be neglected in the passive resistance calculations if the ground surface is not protected from erosion or disturbance by a slab, pavement, or in a similar manner.

4.3.3 Short Drilled Pile Foundations
Axial Capacity
The compressive axial capacity of drilled piles may be estimated based on an allowable skin friction capacity of 200 pounds per square foot. The upper one foot of the skin friction capacity should be ignored. The uplift capacity may be estimated as 70 percent of the allowable compressive axial capacity. A one-third increase in the allowable capacities may be used for transient loading conditions such as wind or seismic loads.

Settlement
Settlement of the proposed canopy supported on drilled piles, as recommended, is estimated to be less than ½ inch. This value does not include elastic compression of the piers under design loads.

Lateral Resistance
The drilled pile foundations lateral resistance can be designed in general accordance with Section 1807.3 of the CBC. We recommend a lateral soil bearing pressure of 250 psf per foot of depth below grade. The lateral soil bearing pressure should not exceed 2,500 psf. Since drilled piles will act as isolated pole foundations, the allowable lateral soil bearing pressure may be increased by a factor of two for short-term lateral loads provided the structure will not be adversely affected by ½ inch of lateral movement at the ground surface.

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4.4 BUILDING SLAB-ON-GRADE
Concrete slab-on-grade floors are appropriate for the proposed warehouse, provided subgrade is prepared in accordance with Section 5.2.2. In accordance with the CWDRs, we recommend the slab be a minimum nominal thickness of 6.0 inches and underlain by at least 6.0 inches of aggregate base material. Aggregate base materials should meet current Caltrans specifications for Class 2 aggregate base. Please note that Caltrans Class 2 aggregate base may utilize recycled materials. Costco typically does not allow the use of recycled materials within the building pad. Alternatively, the aggregate base course could meet the specifications for Crushed Aggregate Base (CAB) as defined in Section 200-2 of the current edition of the Standard Specifications for Public Works Construction (Greenbook).

A modulus of subgrade reaction of 150 pounds per cubic inch may be used for design of slabs underlain by 6.0 inches of aggregate base material. Pursuant to current Costco Wholesale standard construction design practices, we have evaluated whether steel reinforcement is needed in the floor slab. Based on the geotechnical characteristics of the site, the proposed warehouse can be built with a non-reinforced slab.

Floor slab control joints should be used to reduce damage due to shrinkage cracking. Control joint spacing is a function of slab thickness, aggregate size, slump and curing conditions. The requirements for concrete slab thickness, joint spacing, and reinforcement should be established by the designer, based on experience, recognized design guidelines and the intended slab use.

Placement and curing conditions will have a strong impact on the final concrete slab integrity.

It is Costco’s standard practice not to use a vapor retarder below the floor slab due to adverse effects on concrete curing and performance. Kleinfelder has reviewed the subsurface conditions at the site and agrees that a vapor retarder is not necessary below the floor slab. We believe that the Costco warehouse building falls under Exception No. 3 of Section 1907.1 of the CBC. As noted previously, subsurface soil conditions consist generally of granular fill comprised of silty to clayey sand with gravel overlying sandstone of the Capistrano Formation. Additionally, groundwater is deeper than 50 feet below grade. Accordingly, it is our opinion that the migration of moisture through the slab from below will not be detrimental to the intended occupancy of the building. Furthermore, the floor slab is primarily exposed throughout the warehouse and moisturesensitive flooring will not be used.

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4.5 EXTERIOR FLATWORK
Prior to casting exterior flatwork, the subgrade soils should be scarified, moisture conditioned, and recompacted or overexcavated, as recommended in Section 5.2.2. Exterior concrete slabs for pedestrian traffic or landscape outside of the building pad limits should be at least four inches thick. Weakened plane joints in sidewalks should be located at intervals of about 6 feet. Careful control of the water/cement ratio should be performed to avoid shrinkage cracking due to excess water or poor concrete finishing or curing. Unreinforced slabs should not be built in areas where further saturation may occur following construction.

4.6 SITE DRAINAGE
Foundation and slab performance depends greatly on proper irrigation and how well runoff water drains from the site. This drainage should be maintained both during construction and over the entire life of the project. The ground surface around structures should be graded such that water drains away from structures without ponding. The surface gradient needed to do this depends on the landscaping type. Surface gradients should conform to current Costco Wholesale standards and the CBC.

We recommend that landscape planters either not be located adjacent to structures and pavement areas or be isolated and properly drained to area drains such that cycles of wetting and drying do not impact pavements, flatwork, and other structures. Drought resistant plants and minimum watering are recommended for planters, if used. No planters should be installed immediately adjacent to structures unless they are water-proofed and have a drainpipe connected to an area drain outlet. Planters should be built such that water exiting from them will not seep into the foundation areas or beneath slabs and pavement.

Due to poor draining subgrade conditions, we recommend drainage inlets and catch basins include pavement underdrains as shown in Detail 16_16 of the CWDRs. Drains should be designed and constructed per Costco’s standard details and laterals should extend at least 10 feet from the catch basins. Perimeter foundation drains are not necessary.

Where slabs or pavement areas abut landscaped areas, the aggregate base and subgrade soil should be protected against saturation. Vertical cut off structures are recommended to reduce lateral seepage under slabs from adjacent landscaped areas. Vertical cut-off structures may consist of deepened concrete perimeters, or equivalent, extending at least three inches below the base/subgrade interface. Vertical cut-off structures should be poured neat against undisturbed native soil or compacted fill. The cut-off structures should be continuous.

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Operations personnel should be instructed to limit irrigation to the minimum level necessary to properly sustain landscaping plants. Should excessive irrigation, waterline breaks or unusually high rainfall occur, saturated zones and “perched” groundwater may develop, which could soften subgrade and reduce pavement life, and could also create potholes. We also recommend that the downspouts from roof drains be connected to a designed subsurface drainage system such as a storm sewer, etc. to avoid discharging water onto pavement areas and backfill zones around the warehouse.

Potential sources of water such as water pipes, drains, and the like should be frequently examined for signs of leakage or damage. Any such leakage or damage should be promptly repaired. Sewer lines beneath the warehouse should have a sufficient slope (at least 1 percent). Plumbing and utility lines should be provided with flexible joints or oversized sleeves where they penetrate floor slabs to prevent breakage caused by differential slab movement. In addition, utility trenches should be plugged with cohesive backfill where they enter the building to reduce moisture infiltration along pipe bedding material. The cohesive backfill materials should have a plasticity index (PI) between 15 and 30 and no less than 70 percent of the particles passing the No. 200 sieve.

4.7 RETAINING STRUCTURES
Design earth pressures for retaining structures depend primarily on the allowable wall movement, wall inclination, type of backfill materials, backfill slopes, surcharges, and drainage. The earth pressures provided assume that granular (sandy) soils will used as backfill. The on-site clayey soils should not be used as retaining wall backfill. Granular backfill, which should meet the requirements for imported fill as defined in Section 5.2.4, should extend behind walls a horizontal distance of at least one-half the height of the wall (a gravel backdrain may be included in this zone). Determination of whether the active or at-rest condition is appropriate for design will depend on the flexibility of the walls. Walls that are free to rotate at least 0.002 radians (deflection at the top of the wall of at least 0.002 x H, where H is the unbalanced wall height) may be designed for the active condition. Walls that are not capable of this movement should be assumed rigid and designed for the at-rest condition. The recommended active and at-rest earth pressures and passive resistance values are provided in Table 3.

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Table 3
Lateral Earth Pressures For Retaining Structures
(Granular Backfill)
Wall Movement Backfill Condition Equivalent Fluid
Pressure (pcf)
Seismic Increment
(pcf)
Free to Deflect
(active condition) Level
40 18*
Restrained
(at-rest condition) 60 N/A**
Note: * Walls supporting more than 6 feet of backfill should be designed to support an incremental seismic lateral pressure, which is applied as a triangular pressure distribution with a maximum pressure at the bottom of the wall, applied similar to the active lateral earth pressure. ** for restrained walls, use the static active earth pressure plus the seismic increment to check the seismic condition; use at-rest earth pressure only to check the static condition; the larger loading of both cases should be used for the design of restrained wall.

The above lateral earth pressures do not include the effects of surcharges (e.g., traffic, footings), compaction, or truck-induced wall pressures. Any surcharge (live, including traffic, or dead load) located within a 1:1 (horizontal to vertical) plane drawn upward from the base of the excavation should be added to the lateral earth pressures. The lateral contribution of a uniform surcharge load located immediately behind walls may be calculated by multiplying the surcharge by 0.33 for cantilevered walls under active conditions and 0.50 for restrained walls under at-rest conditions.

Walls adjacent to areas subject to vehicular traffic should be designed for a 2-foot equivalent soil surcharge (250 psf). Lateral load contributions from other surcharges located behind walls may be provided once the load configurations and layouts are known.

Walls should be properly drained or designed to resist hydrostatic pressures. Adequate drainage is essential to provide a free-drained backfill condition so that there is no hydrostatic buildup behind the wall. Walls should also be appropriately waterproofed to reduce the potential for staining. Drainage behind loading dock walls can consist of weep holes placed along the base of the wall. Weep holes should be spaced 10 to 15 feet apart and connected with a gravel drain consisting of approximately 2 cubic feet of clean gravel per foot of wall length wrapped with filter fabric. Drains should be provided within the loading dock areas to collect both surface water and any seepage from the weep holes. Other types of retaining walls should have a continuous back drain as described below.

For backfill of walls with a continuous back drain, except for the upper 2 feet, the backfill immediately behind retaining walls (minimum horizontal distance of 2 feet measured perpendicular to the wall) should consist of free-draining ¾-inch crushed rock wrapped with filter fabric. The upper 2 feet of cover backfill should consist of relatively impervious material. A Item: 11
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4-inch-diameter perforated PVC pipe, placed perforations down at the bottom of the rock layer leading to a suitable gravity outlet, should be installed at the base of the walls.

As an alternative to the gravel drain noted above, a manufactured drain panel may be utilized behind retaining walls in addition to normal waterproofing. This system generally consists of a prefabricated drain panel lined with filter fabric. At the wall base, we recommend that a gravel drain be installed to collect and discharge drainage to a suitable outlet. The drain should consist of a 4-inch-diameter perforated PVC pipe, placed perforations down at the bottom of approximately 2 cubic feet of clean gravel per foot of wall length. The gravel drain should be wrapped in filter fabric (Mirafi 140N or equivalent). The pipe should be sloped to drain to a suitable outlet and cleanouts should be provided at appropriate intervals.

If drainage behind the wall is omitted, the wall should be designed for full hydrostatic pressure.

The design of any drain system should be submitted to Kleinfelder for review to check that our recommendations have been properly incorporated into the design. Installation of the drainage system should be reviewed and documented by a Kleinfelder representative.

4.8 PAVEMENT SECTIONS
The required pavement structural sections will depend on the expected wheel loads, volume of traffic, and subgrade soils. We have provided asphalt concrete pavement sections for traffic indices provided in the CWDRs (Costco, 2022). Positive drainage of the paved areas should be provided since moisture infiltration into the subgrade may decrease the life of pavements. Curbing located adjacent to paved areas should be founded in the subgrade, not the aggregate base, in order to provide a cutoff, which reduces water infiltration into the base course.

The following pavement sections provided above are based on the soil conditions encountered during our field exploration, our assumptions regarding final site grades, and limited laboratory testing.

4.8.1 Costco Pavement Design Parameters
We developed pavement design recommendations using traffic loading parameters provided in the Costco Wholesale Development Requirements and the following test data:
• A 20-year pavement design life.
• Light-duty pavements subject to 6,600 passenger vehicle trips per day (Traffic Index of

5.0).

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• Heavy-duty pavements subject to 30 tractor-trailer truck tips per day (Traffic Index of 7.0). • For asphalt concrete pavements, a design R-value of 15 based on laboratory testing and engineering judgement.
• For Portland cement concrete (PCC) Pavements, a 28-day flexural strength (modulus of rupture determined by the third-point method) of at least 550 pounds per square inch (psi) (approximate compressive strength of 4,000 psi); a modulus of subgrade reaction (k value) of 100 pounds per cubic inch (pci) for native subgrade; and interlock at the control joints.

4.8.2 Asphalt Concrete Pavement
We designed asphalt concrete pavement, also referred to as Hot Mix Asphalt (HMA), in general accordance with the Caltrans Highway Design Manual (2022), which is the current design practice in California. Table 4 presents the asphalt concrete pavement sections for the noted traffic indices.

The designer should select the appropriate pavement sections based on projects requirements.

Prior to placement of aggregate base, pavement subgrade should be prepared in accordance with Section 5.2.2.

Table 4
Recommended Minimum Asphalt Concrete Pavement Sections
Traffic Use Traffic Index, TI Design Method
Asphalt
Concrete*
(inches)
Aggregate Base*
(inches)
Light-Duty
Pavement 5.0 Caltrans 4.0 6.0
Heavy-Duty
Pavement 7.0 Caltrans 5.0 11.5
* Rounded to the closest ½ inch.

4.8.3 Asphalt Performance Grade Binder
An asphalt performance grade (PG) binder of 64-10 should be used for the project and is locally available. This recommendation was developed in accordance with Costco Wholesale Asphalt Paving Specification Section 321216. Air temperature data nearest the project site was used with the MERRA Climate Data option and the PG binder was selected using the FHWA program LTTPBind Online web-based tool based on the AASHTO M323-13 standard. The high-end and low-end temperature rating was selected to provide a reliability of at least 98 and 90 percent, respectively.

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4.8.4 Portland Cement Concrete Pavement
We designed PCC pavement in accordance with the Portland Cement Association (PCA) Thickness Design for Concrete Pavements (PCA, 1984) using the design parameters stated above. For heavy-duty pavements, we recommend that PCC pavement section should be comprised of 7.0 inches of PCC with 6.0 inches of aggregate base. We understand that Costco is considering paving the American Disability Act (ADA) access area in front of the main entry with PCC pavement. For ADA access area, we recommend that PCC pavement section should be comprised of 6.0 inches of PCC with 6.0 inches of aggregate base to match the building pad flatwork. Prior to placement of aggregate base, pavement subgrade should be prepared in accordance with Section 5.2.2.

Longitudinal and transverse joint spacing should not exceed 12 feet and 15 feet, respectively.

Joint details should conform to PCA guidelines. Expansion joints in concrete slabs should be sealed with petroleum resistant sealant to prevent minor releases from impacting subsurface soil.

4.8.5 Aggregate Base
Aggregate base materials should meet current Caltrans specifications for Class 2 aggregate base.

4.8.6 Pavement Maintenance
Pavements may undergo movement due to changes in subgrade moisture content. This movement tends to accelerate pavement deterioration. A crack sealing program should be performed annually to slow pavement deterioration. Any areas where surface water stands on the surface should be remediated. Over time, as cracking becomes more pronounced, a slurry seal coat should be applied.

4.9 SOIL CORROSIVITY
We performed laboratory testing for parameters commonly used to evaluate corrosivity of soils, including pH, minimum resistivity, chloride and soluble sulfate content. Table 5 presents the results.

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Table 5
Corrosion Test Results
Location Depth
(ft)
Minimum
Resistivity
(ohm-cm)
pH
Soluble
Sulfate
Content
(ppm)
Soluble
Chloride
Content
(ppm)
B-2 0-5 2,767 8.0 37 6
B-11 0-5 3,147 8.0 8 4
B-16 0-5 1,907 8.4 119 12
B-27 0-5 2,048 8.7 101 9
These tests are a generalized indicator of soil corrosivity for the samples tested. Other soils on site may be more, less, or similarly corrosive in nature. Imported fill materials should be tested to confirm that their corrosion potential is not more severe than those noted.

Although Kleinfelder does not practice corrosion engineering, resistivity values between 1,000 and 3,000 ohm-cm are normally considered highly corrosive to buried ferrous metals (Roberge, 2006). The concentrations of soluble sulfates indicate that the subsurface soils represent a Class S0 Class S0 exposure to sulfate attack on concrete in contact with the soil based on ACI 318-19 Table 19.3.1.1. Therefore, in accordance with ACI Building Code 318-19, no special provisions for selection of cement type are required.

4.10 STORMWATER MANAGEMENT
We understand that as part of the storm water management for the project, Infiltration Best Management Practices (BMPs), are being considered. We performed four (4) borehole percolation tests in general accordance with Appendix VII of the Orange County Technical Guidance Document for Preparation of Conceptual/Preliminary and/or Project Water Quality Management Plans, dated December 20, 2013. We also performed sieve analysis and hydrometer testing to assess the grain-size characteristics of the onsite soils. The results of the laboratory testing and infiltration testing results are attached in Appendix B and C, respectively.

Based on visual soil classification and laboratory testing of the soil samples collected during our field exploration, the near-surface soils generally consist of artificial fill comprised of silty to clayey sand overlying Capistrano Formation sandstone. The fines content of the infiltration test samples tested during our field exploration ranged from approximately 8 to 20 percent based on laboratory testing of the near surface soils. Table 6 summarizes the tested (in-situ) infiltration rates and the long-term design infiltration rates for each test location.

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Table 6
Summary of Infiltration Test Results
Test
Location
Approximate Test Depth
(feet bgs)
Tested Infiltration Rate
(inches per hour)
Design Infiltration Rate
(inches per hour)1
INF-1 3 – 5 0.3 0.07
INF-2 8 – 10 0.1 0.02
INF-3 3 – 5 0.1 0.02
INF-4 8 – 10 0.1 0.02
Notes: 1Design Infiltration Rate determined using a combined factor of safety of 4.4, as recommended in Worksheet H: Factor of Safety and Design Infiltration Rate and Worksheet in the Orange County Technical Guidance Document for Preparation of Conceptual/Preliminary and/or Project Water Quality Management Plans, dated December 20, 2013.

Based on the results of the infiltration testing and laboratory testing, it is our opinion that the site is not considered suitable for infiltration BMPs in the subsurface soils as shown by the infiltration rates provided in Table 6. We recommend alternatives to infiltration Best Management Practices (BMPs), such as bio-filtration/bio-retention systems (bio-swales and planter boxes), be implemented at the warehouse site. If bio-filtration/bio-retention systems are employed, we recommend that the BMPs be built such that water exiting from them will not seep into the foundation areas or beneath slabs and pavement. If planters are located within 10 feet of the building or building foundations, or adjacent to slabs and pavements, then some means of diverting water away from the building, building foundation soils, or soils that support slabs and pavements would be required, such as lining the planters.

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5 CONSTRUCTION RECOMMENDATIONS

5.1 GENERAL
The following recommendations should be used by the contractor for construction of the project.

5.2 EARTHWORK

5.2.1 General
Site preparation and earthwork operations should be performed in accordance with applicable codes, safety regulations and other local, state or federal specifications, and the recommendations included in this report. References to maximum dry unit weights are established in accordance with the latest version of ASTM Test Method D1557 (modified Proctor).

The earthwork operations should be observed and tested by a representative of Kleinfelder.

5.2.2 Site Preparation
Abandoned utilities and other existing features within the proposed development areas (if any are encountered) should be removed and the excavation(s) backfilled with engineered fill. Debris produced by demolition operations, including wood, steel, piping, plastics, etc., should be separated and disposed of off-site. Existing utility pipelines or conduits that extend beyond the limits of the proposed construction and are to be abandoned in place, should be plugged with non-shrink cement grout to prevent migration of soil and/or water. Demolition, disposal, and grading operations should be observed and tested by a representative of Kleinfelder.

Soils within 10 feet of the warehouse pad (including the entrance canopy, building aprons, utility pads, stairs, ramps, stoops, and the loading dock) should be overexcavated to a depth of at least 5 feet below existing grade or 3 feet below the bottom of the footings and floor slabs, whichever is deeper, and replaced as structural fill. Depending on the condition of the fill at the base of the excavation, additional overexcavation may be required. The overexcavated soils can be moisture conditioned and recompacted as structural fill. Following overexcavation and prior to replacing soils, the exposed subgrade should be proof-rolled with heavy construction equipment (e.g., with a fully-loaded tandem-axle dump truck or water truck). Areas identified as being soft or yielding may require additional compaction or overexcavation as determined by Kleinfelder.

For pavement, sidewalk, and other flatwork areas, we recommend that the exposed subgrade be proof-rolled with heavy construction equipment (e.g. loader or smooth-drum roller) after the area Item: 11
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has been stripped of soft earth materials and construction debris to disclose areas of soft and yielding material. Where soft and yielding material is observed, it should be overexcavated and replaced as structural fill. The proof-rolling should extend beyond the proposed improvements a horizontal distance of at least 2 feet, where possible.

For the retaining wall on the west boundary of the site, soils should be overexcavated to a depth of at least 2 feet below existing grade or 2 feet below the bottom of the footing, whichever is deeper. The overexcavated soils can be moisture conditioned and recompacted as structural fill.

The overexcavation should extend beyond the proposed improvements a horizontal distance of at least 2 feet.

Following overexcavation and prior to replacing soils, the exposed subgrade should be proof rolled with at least a 10-ton roller, fully loaded tandem-axle dump truck or water truck. Areas identified as being soft or yielding may require additional compaction or overexcavation as determined by Kleinfelder. Following proof rolling and any additional overexcavation, the exposed subgrade should be scarified at least 6 to 8 inches, moisture conditioned, and recompacted.

5.2.3 Foundation Excavations
Shallow Foundations
Following excavation to the foundation subgrade elevations, the exposed subgrade should be observed by a representative of the geotechnical engineer to evaluate the presence of satisfactory materials at design elevations. If unsatisfactory material, such as soft or disturbed soil, debris or otherwise unsuitable soil is present at the base of footing excavations, it should be overexcavated and replaced with structural concrete, 2-sack sand-cement slurry, or structural fill to the depth determined by the geotechnical engineer.

Drilled Pile Foundations
The performance and capacities of piles can be influenced significantly by the selected construction methods and procedures used. Construction methods that create large zones of disturbance around the drilled shafts can lead to lower than expected skin friction due to excessive stress relief around the shaft length. Drilling of the pile shafts should be accomplished using conventional heavy-duty excavation equipment maintained in good condition. However, drilling of the pile shafts may require heavy-duty excavation equipment, and possibly rock coring equipment, to excavate through the Capistrano Formation sandstone.

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Caving of the pile shafts could occur in non-cohesive sandy layers. Temporary steel casing may be required to stabilize the sides of the pile shaft. Concrete should be placed immediately after drilling of the hole is complete. The concrete should be pumped to the bottom of the drilled shaft using a down-hole tremie. If the tremie method is used to place concrete below the water level, we recommend it have a slump of at least 8 inches. If steel casing is used, the casing should be removed as the concrete is placed but the bottom of the casing should be kept at least 5 feet below the top of the concrete.

5.2.4 Fill Material and Compaction Criteria
The on-site soils, minus debris, organic matter, or other deleterious materials may be used as structural fill. Rock or other soil fragments greater than 3 inches in size should not be used in the fills.

Import soils, if needed, should have no particles greater than 3 inches in maximum dimension, no less than 70 percent of the particles passing the No. 4 sieve, no more than 30 percent of particles passing the No. 200 sieve, and a Plasticity Index (PI) less than 5. The contractor should provide documentation that all imported soil is free of hazardous materials, including petroleum or petroleum byproducts, chemicals and harmful minerals. Test results with the geotechnical and analytical properties of the proposed import material should be provided to Costco for approval prior to transportation and use on site.

Soils should be compacted to at least 95 percent of the maximum dry unit weight (ASTM D1557) in accordance with the Costco Wholesale Development Requirements (CWDRs). Fill should be placed in loose horizontal lifts not more than 8 inches thick (loose measurement). The moisture content of the fill should be maintained at within 2 percent of optimum during compaction.

Processing may require ripping the material, disking to break up clumps, and blending to attain uniform moisture contents necessary for compaction. Utility trench backfill should be mechanically compacted. Flooding should not be permitted. Table 7 presents structural fill placement and compaction criteria.

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Table 7
Structural Fill Placement And Compaction Criteria
Fill Location/Use Material
Type
Relative Compaction1
(ASTM D1557)
Moisture
Content
Range
Minimum
Compaction
Testing Frequency
Per Lift
Aggregate Base
Course for
Pavements and
Concrete Slabs
Aggregate
Base At least 95 percent -2 to +2%of optimum 10,000 Square Feet Structural Areas
(Warehouse
Building Pad)
On-site Soils
or Imported
Material
At least 95 percent -2 to +2%
of optimum 10,000 Square Feet
Subgrade for
Pavements,
Sidewalks and
Other Flatwork
Areas
On-site Soils
or Imported
Material
At least 95 percent -2 to +2%
of optimum 15,000 Square Feet
Retaining Wall
Backfill
On-site
Granular
Soils or
Imported
Material
At least 92 percent -2 to +2%
of optimum 1,000 Square Feet
Utility Trenches
Backfill
On-site Soils
or Imported
Material
At least 95 percent -2 to +2%
of optimum 150 Linear Feet
Lawns or
Unimproved Areas
On-site Soils
or Imported
Material
At least 90 percent At least
optimum 20,000 Square Feet
Note: 1 Where two or more compaction specifications coincide, the more stringent specification should be utilized.

5.2.5 Shrinkage/Bulking
For earthwork volume estimating purposes, an average shrinkage value of 5 to 10 percent for the upper fill soils (generally in the upper 5 to 6 feet) may be assumed. These values are estimates only and exclude losses due to removal of vegetation or debris. Actual shrinkage/bulking factors will depend on the types of earthmoving equipment used and should be determined during grading. We recommend that the civil engineer or the contractor contact a local earthwork contractor to confirm these values prior to finalizing any earthwork estimates.

5.2.6 Excavation Characteristics
The subsurface conditions consist predominantly of artificial fill overlying Capistrano Formation sandstone. Refusal was not encountered in any of the borings drilled to a maximum depth of approximately 49½ feet bgs. The excavations for foundations, utility trenches and general site grading should be excavatable with conventional heavy-duty construction equipment maintained Item: 11
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in good condition; however, localized cemented zones may require more aggressive means of excavation such as a large hydraulic excavator equipped with either a rock ripping attachment or a pneumatic hammer to break up and excavate the bedrock. The contractor should consider these soil conditions in determining the equipment required for the on-site excavations. In addition, oversized materials, such as rock fragments or cobbles, should be anticipated. Oversize material larger than 3 inches in diameter should be removed and disposed of off-site. Caving of the sidewalls during excavation in the sandy soil may occur depending on conditions at the time of excavation and should be anticipated by the contractor.

5.2.7 Temporary Excavations
All excavations must comply with applicable local, state, and federal safety regulations, including OSHA requirements. The responsibility for excavation safety and stability of temporary construction slopes lies solely with the contractor. We are providing this information below solely as a service to our client. Under no circumstances should this information provided be interpreted to mean that Kleinfelder is assuming responsibility for final engineering of excavations or shoring, construction site safety, or the contractors’ activities; such responsibility is not being implied and should not be inferred.

Minor sloughing and/or raveling of slopes should be anticipated as they dry out. Where space for sloped embankments is not available, shoring will be necessary. In addition, excavations within a 1:1 plane extending downward from a horizontal distance of 2 feet beyond the bottom outer edge of existing improvements should not be attempted without bracing and/or underpinning the footings, as discussed above. The geotechnical engineer or their field representative should observe the excavations so that modifications can be made to the excavations, as necessary, based on variations in the encountered soil conditions. All applicable excavation safety requirements and regulations, including OSHA requirements, should be met.

Vertical or steeply sided trench excavations should not be attempted without proper shoring or bracing. All trench excavations should be braced and shored in accordance with good construction practice and all applicable safety ordinances and codes. Stockpiled (excavated) materials should be placed no closer to the edge of an excavation than a distance equal to the depth of the excavation, but no closer than 4 feet.

5.2.8 Trench Backfill
Pipe zone backfill (i.e. material beneath and in the immediate vicinity of the pipe) should consist of imported soil less than ¾-inch in maximum dimension. Trench zone backfill (i.e., material Item: 11
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placed between the pipe zone backfill and finished subgrade) may consist of onsite soil or imported fill that meets the requirements for engineered fill provided above.

If imported material is used for trench zone backfill, we recommend it consist of silty sand. In general, gravel should not be used for trench zone backfill due to the potential for soil migration into the relatively large void spaces present in this type of material and for water seepage along trenches backfilled with coarse-grained sand and/or gravel.

Recommendations provided above for pipe zone backfill are minimum requirements only. More stringent material specifications may be required to fulfill local building requirements and/or bedding requirements for specific types of pipes. We recommend the project civil engineer develop these material specifications based on planned pipe types, bedding conditions, and other factors beyond the scope of this study.

Trench backfill should be placed and compacted in accordance with recommendations provided for engineered fill in Section 5.2.4. Mechanical compaction is recommended; ponding or jetting should be avoided, especially in areas supporting structural loads or beneath concrete slabs supported on grade, pavements, or other improvements.

5.3 UNSTABLE SUBGRADE CONDITIONS
Should grading be performed during or following extended periods of rainfall, the moisture content of the near-surface soils may be significantly above the optimum moisture content. These conditions could seriously impede grading by causing an unstable subgrade condition. Typical remedial measures for the site conditions include the following. • Drying: Drying unstable subgrade involves disking or ripping wet subgrade to a depth of approximately 18 to 24 inches and allowing the exposed soil to dry. Multiple passes of the equipment (likely on a daily basis) will be needed because as the surface of the soil dries, a crust forms that reduces further evaporation. Frequent disking will help prevent the formation of a crust and will promote drying. This process could take several days to several weeks depending on the material, the depth of ripping, the number of passes, and the weather.
• Removal and Replacement with Crushed Rock and Geotextile Fabric: Unstable subgrade could be overexcavated 12 to 24 inches below existing grade and replaced with ¾- or 1-inch crushed rock underlain by geotextile fabric. The geotextile fabric should consist of a woven geotextile, such as Mirafi HP series or equivalent. The final depth of removal will Item: 11
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depend upon the conditions observed in the field once overexcavation begins. The geotextile fabric should be placed in accordance with the manufacturer’s recommendations.
• Cement Treatment: For larger areas, unstable subgrade could be stabilized by mixing the upper 12 to18 inches of the subgrade with Portland cement. For estimating purposes, an application rate of 4 to 5 percent Portland cement may be used. Final application rates should be determined in the field at the time of construction in consultation with the geotechnical engineer. Cement treatment should be performed by a specialty contractor experienced in this work. Since soil treatment uses the on-site soil, the expense of importing material can be avoided.

5.4 TEMPORARY SHORING
Temporary shoring may be required in areas adjacent to existing structures or improvements where excavations cannot be adequately sloped. Temporary shoring may consist of a turn-key shoring system, soldier piles and lagging, or other system. Recommendations for design of temporary shoring are presented below.

The shoring design should be provided by a civil engineer registered in the State of California and experienced in the design and construction of shoring under similar conditions. Once the final excavation and shoring plans are complete, the plans and design should be reviewed by Kleinfelder for conformance with the design intent and geotechnical recommendations provided herein.

5.4.1 Lateral Pressures
For the design of cantilevered shoring, an equivalent fluid pressure of 40 pounds per cubic foot (pcf) may be used for level backfill. Where the surface of the retained earth slopes up away from the shoring, a greater pressure should be used. Design data can be developed for additional cases when the design conditions are established.

In addition to the recommended earth pressure, any surcharge (live, including traffic, or dead load) located within a 1:1 plane drawn upward from the base of the shored excavation should be added to the lateral earth pressures. The lateral contribution of a uniform surcharge load located immediately behind the wall may be calculated by multiplying the surcharge by 0.33 for the level backfill condition. Lateral load contributions of surcharges located at a distance behind the shored wall may be provided once the load configurations and layouts are known. As a minimum, a 2- Item: 11
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foot equivalent soil surcharge (250 psf) is recommended to account for nominal construction loads. It should be noted that the above pressures do not include hydrostatic pressure and assume groundwater will not be encountered in the excavation, or dewatering will be used to lower the ground water table below the bottom of the excavation.

5.4.2 Design of Soldier Piles
All soldier piles should extend to a sufficient depth below the excavation bottom to provide the required lateral resistance. We recommend the required embedment depths be calculated based on the principles of force and moment equilibrium. For this method, the allowable passive pressure against soldier piles that extend below the level of excavation may be assumed to be equivalent to a fluid pressure of 250 pcf. The maximum lateral resistance value should not exceed 2,500 psf. To account for arching, the passive resistance may be assumed to act over a width 2.5 times the width of the embedded portion of the pile, provided adjacent piles are spaced at least

3.0 pile diameters, center-to-center.

Drilling of the soldier pile shafts could be accomplished using heavy-duty drilling equipment. The on-site soils below the base of the excavation are sandy and caving of the pile shafts could occur.

Temporary steel casing may be required to stabilize the sides of the pile shaft. Concrete for piles should be placed immediately after the drilling of the hole is complete. The concrete should be pumped to the bottom of the drilled shaft using a tremie. Once concrete pumping is initiated, a minimum head of 5 feet of concrete above the bottom of the tremie should be established and maintained throughout the concrete placement to prevent contamination of the concrete by soil inclusions. If steel casing is used, the casing should be removed as the concrete is placed.

To develop full lateral resistance, provisions should be taken to assure firm contact between the soldier piles and undisturbed materials. The concrete placed in the soldier pile excavations may be a lean-mix concrete. However, the concrete used in that portion of the soldier pile that is below the planned excavated level should provide sufficient strength to adequately transfer the imposed loads to the surrounding materials.

5.4.3 Lagging
Continuous treated timber lagging should be used between the soldier piles. The lagging should be installed as the excavation proceeds. If treated timber is used, the lagging may remain in place after backfilling. The lagging should be designed for the recommended earth pressure but limited to a maximum value of 400 psf.

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5.4.4 Deflection
Shoring adjacent to existing structures or improvements should be designed and constructed to reduce potential movement. The shoring system designer should evaluate potential deflections in their design.

5.4.5 Monitoring
Some deflection of the shored excavation should be anticipated during the planned excavation.

We recommend the project civil engineer perform a survey of all existing utilities and structures adjacent to the shored excavation. The purpose of this survey would be to evaluate the ability of existing utility lines or improvements to withstand horizontal movements associated with a shored excavation and to establish the baseline condition in case of unfounded claims of damage. If existing improvements are not capable of withstanding anticipated lateral movements, alternative shoring systems may be required.

Horizontal and vertical movements of the shoring system should be monitored by a licensed surveyor. The construction monitoring and performance of the shoring system are ultimately the contractor’s responsibility. However, at a minimum, we recommend that the top of shoring be surveyed prior to excavation and that the top and bottom of the soldier beams be surveyed on a weekly basis until the shoring is not needed. Surveying should consist of measuring movements in vertical and two perpendicular horizontal directions.

5.5 EXTERIOR FLATWORK
Prior to casting exterior flatwork, the existing soils should be overexcavated and subgrade soils should be scarified, moisture conditioned, and recompacted as recommended in Section 5.2.2.

The moisture content of the finished subgrade soils should be maintained around optimum prior to the placement of any flatwork or structural fill. Careful control of the water/cement ratio should be performed to avoid shrinkage cracking due to excess water or poor concrete finishing or curing.

5.6 PAVEMENTS

5.6.1 HMA Design
Hot Mix Asphalt (HMA) should conform to requirements of the Costco Wholesale Specification Section 321216, Asphalt Paving. Section 1.3.C of the HMA specification requires that the HMA section be placed in at least two lifts. The HMA specification allows the use of ½- or ¾-inch Nominal Maximum Aggregate Size (NMAS) mixes for the base course and ⅜- or ½-inch NMAS Item: 11
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mixes for surface course. Maximum and minimum HMA compacted lift thicknesses are provided in Table 3.1 in Section 3.3.B of the HMA specification.

5.6.2 Construction Considerations
The pavement sections provided above are contingent on the following recommendations being implemented during construction.
• Pavement subgrade should be prepared as recommended in Section 5.2.2. • Subgrade soils should be in a stable, non-pumping condition at the time the aggregate base materials are placed and compacted.
• Aggregate base materials should be compacted to at least 95 percent relative compaction (ASTM D1557).
• Asphalt paving materials and placement methods should meet current Costco Wholesale Specifications Section 321216.
• Adequate drainage (both surface and subsurface) should be provided such that the subgrade soils and aggregate base materials are not allowed to become wet.

Note that pavement materials and construction must be completed in strict accordance with the Costco’s specifications that contain very specific pavement material (asphalt, aggregate and concrete) criteria and construction practices to be used (compaction and material sampling). The general contractor and pavement construction subcontractor should be aware that asphalt and concrete mix designs must be submitted to the design architect and Kleinfelder at least 45 days prior to the scheduled production and laydown for review and approval.

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6 ADDITIONAL SERVICES

6.1 PLANS AND SPECIFICATIONS REVIEW
We recommend Kleinfelder perform a review of geotechnical-related portions of the project plans and specifications before they are finalized to see that geotechnical recommendations have been properly interpreted and implemented during design. If we are not accorded the privilege of performing this review, we can assume no responsibility for misinterpretation of our recommendations.

6.2 CONSTRUCTION OBSERVATION AND TESTING
The construction process is an integral design component with respect to the geotechnical aspects of a project. Because geotechnical engineering is an inexact science due to the variability of natural processes, and because we sample only a limited portion of the soils affecting the performance of the proposed structure, unanticipated or changed conditions can be encountered during grading. Proper geotechnical observation and testing during construction are imperative to allow the geotechnical engineer the opportunity to verify assumptions made during the design process. Therefore, we recommend that Kleinfelder be retained during the construction of the proposed improvements to observe compliance with the design concepts and geotechnical recommendations, and to allow design changes in the event that subsurface conditions or methods of construction differ from those assumed while completing this study.

Our services are typically needed at the following stages of grading:
• After demolition;
• During grading;
• During the installation of temporary construction shoring; • After the overexcavation, but prior to subgrade preparation; • During utility trench backfill;
• During fill placement of wall backfill;
• During base placement and site paving; and
• After excavation for foundations.

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7 LIMITATIONS
This geotechnical study has been prepared for the exclusive use of Costco Wholesale and their agents for specific application to the proposed Costco Wholesale Warehouse (CW# 24-1218) located at 26602 Towne Centre Drive in Foothill Ranch, California. The findings, conclusions, and recommendations presented in this report were prepared in accordance with generally accepted geotechnical engineering practice. No other warranty, express or implied, is made.

The scope of services was limited to a background data review and the field exploration described in Section 1.2. It should be recognized that definition and evaluation of subsurface conditions are difficult. Judgments leading to conclusions and recommendations are generally made with incomplete knowledge of the subsurface conditions present due to the limitations of data from field studies. The conclusions of this assessment are based on our field exploration and laboratory testing programs, and engineering analyses.

Kleinfelder offers various levels of investigative and engineering services to suit the varying needs of different clients. Although risk can never be eliminated, more detailed and extensive studies yield more information, which may help understand and manage the level of risk. Since detailed study and analysis involves greater expense, our clients participate in determining levels of service, which provide information for their purposes at acceptable levels of risk. The client and key members of the design team should discuss the issues covered in this report with Kleinfelder, so that the issues are understood and applied in a manner consistent with the owner’s budget, tolerance of risk and expectations for future performance and maintenance.

Recommendations contained in this report are based on our field observations and subsurface explorations, limited laboratory tests, and our present knowledge of the proposed construction. It is possible that soil or groundwater conditions could vary between or beyond the points explored. If soil or groundwater conditions are encountered during construction that differ from those described herein, the client is responsible for ensuring that Kleinfelder is notified immediately so that we may reevaluate the recommendations of this report. If the scope of the proposed construction, including the estimated Traffic Index or locations of the improvements, changes from that described in this report, the conclusions and recommendations contained in this report are not considered valid until the changes are reviewed, and the conclusions of this report are modified or approved in writing, by Kleinfelder.

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The scope of services for this subsurface exploration and geotechnical report did not include environmental assessments or evaluations regarding the presence or absence of wetlands or hazardous substances in the soil, surface water, or groundwater at this site.

Kleinfelder cannot be responsible for interpretation by others of this report or the conditions encountered in the field. Kleinfelder must be retained so that all geotechnical aspects of construction will be monitored on a full-time basis by a representative from Kleinfelder, including site preparation, preparation of foundations, and placement of engineered fill and trench backfill. These services provide Kleinfelder the opportunity to observe the actual soil and groundwater conditions encountered during construction and to evaluate the applicability of the recommendations presented in this report to the site conditions. If Kleinfelder is not retained to provide these services, we will cease to be the engineer of record for this project and will assume no responsibility for any potential claim during or after construction on this project. If changed site conditions affect the recommendations presented herein, Kleinfelder must also be retained to perform a supplemental evaluation and to issue a revision to our original report.

This report, and any future addenda or reports regarding this site, may be made available to bidders to supply them with only the data contained in the report regarding subsurface conditions and laboratory test results at the point and time noted. Bidders may not rely on interpretations, opinion, recommendations, or conclusions contained in the report. Because of the limited nature of any subsurface study, the contractor may encounter conditions during construction which differ from those presented in this report. In such event, the contractor should promptly notify the owner so that Kleinfelder’s geotechnical engineer can be contacted to confirm those conditions. We recommend the contractor describe the nature and extent of the differing conditions in writing and that the construction contract include provisions for dealing with differing conditions. Contingency funds should be reserved for potential problems during earthwork and foundation construction.

This report may be used only by the client and only for the purposes stated, within a reasonable time from its issuance, but in no event later than one year from the date of the report. Land use, site conditions (both on site and off site) or other factors may change over time, and additional work may be required with the passage of time. Any party, other than the client who wishes to use this report shall notify Kleinfelder of such intended use. Based on the intended use of this report and the nature of the new project, Kleinfelder may require that additional work be performed and that an updated report be issued. Non-compliance with any of these requirements by the client or anyone else will release Kleinfelder from any liability resulting from the use of this report by any unauthorized party and the client agrees to defend, indemnify, and hold harmless Kleinfelder from any claims or liability associated with such unauthorized use or non-compliance.

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8 REFERENCES
American Concrete Institute (ACI), 2019. Building Code Requirements for Structural Concrete (ACI 318-19) and Commentary (ACI318-19R).

American Society of Civil Engineers (ASCE), 2016, Minimum Design Load for Buildings and Other Structures (ASCE/SEI 7-16) with ASCE Supplement 1, 2, and 3.

California Department of Conservation, Geologic Energy Management Division (CalGEM), 2024, Well Finder, Well Finder (ca.gov)
California Geological Survey (CGS), 2025. California Landslide Inventory and Susceptibility to Deep-Seated Landslides in California (2011). Landslide Inventory Beta. Landslide Inventory (Beta) (ca.gov) Accessed February, 2025.

California Geological Survey (CGS), 2018, Earthquake Fault Zones - A Guide for Government Agencies, Property Owners/Developers, and Geoscience Practitioners for Assessing Fault Rupture Hazards in California: California Geological Survey Special Publication 42, 83p.

California Geological Survey (CGS), 2003, Earthquake Fault Zones, Corona South Quadrangle, California 7.5 Minute Series: California Geological Survey, Revised Official Map Effective May 1, 2003.

California Geologic Survey (CGS), 2002, California Geomorphic Provinces, Note 36, California Dept. of Conservation, Sacramento, California.

California Geological Survey (CGS), 2001, Earthquake Zones of Required Investigations, 7.5- Minute Lake Forest Quadrangle (Previously El Toro Quadrangle); Official Map, released January 17, 2001.

Cao, T., Bryant, W.A., Rowshandel, B., Branum, D., and Wills, C.J., 2003, The Revised 2002 California Probabilistic Seismic Hazard Maps, California Geological Survey, available at "http://www.conservation.ca.gov/"
Costco, 2024. Costco Wholesale Development Requirements, Version 2024, dated October 31, 2022.

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Dawson, T.E., and R.J. Weldon, 2013, Appendix B - Geologic Slip Rate Data and Geologic Deformation Model in Field, et al. 2013, Uniform California earthquake rupture forecast, version 3 (UCERF3) - The time-independent model: U.S. Geological Survey (USGS) Open-File Report 2013–1165, and California Geological Survey (CGS) Special Report 228.

Division of Safety of Dams, 2025, Dam Breach Inundation Map Web Publisher. Dam Breach Inundation Map Web Publisher (ca.gov), Accessed February 2025.

Federal Emergency Management Agency (FEMA), 2009, FIRM, Flood Insurance Rate Map, City of Lake Forest, California, Map Number 06059C0316J, Effective Date December 3, 2009 Grant, L.B. , Ballenger, L.J., and Runnerstrom, E.E., 2002, Coastal Uplift of the San Joaquin Hills, Southern Los Angeles Basin, California, by a Large Earthquake since A.D. 1635: Bulletin of the Seismological Society of America, Volume 92, No. 2, pp. 590-599 Grant, L.B., Mueller, K. J., Gath, E. M., Cheng, H., Edwards, R. L., Munro, R., and Kennedy, G.

L., 1999, Late Quaternary uplift and earthquake potential of the San Joaquin Hills, southern Los Angeles basin, California: Geology, Volume 27, No. 11, pp. 1031–1034.

International Code Council, Inc., 2022 California Building Code.

Kimley-Horn and Associates, Inc., 2025, Preliminary Overall Grading Plan, Warehouse Preliminary Set, Foothill Ranch, Sheet No. 4, dated March 14, 2025.

MG2, 2024, Concept Site Plan, Costco Wholesale, Foothill Ranch, CA, Sheet DD11-01, dated March 7, 2024.

Montrose Environmental, 2025, Second Semi-Annual 2024 Groundwater Monitoring Report Former Palisades Gas and Wash Station No. 824 26731 Portola Parkway, Lake Forest, California, Project No. 006531, Case No. 14UT002, dated January 9, 2025 Morton, D.M. and Miller, F.K., 2006, Geologic map of Santa Ana 30’ x 60’ Quadrangle, California:

United States Geological Survey Open-File Report 2006-1217, scale 1:100,000.

Orange County Water District (OCWD), City of La Habra and Irvine Ranch Water District (IRWD), 2022, Basin 8-1 Alternative 2022 Update, dated January 1, 2022.

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PBLA Surveying, Inc., 2025, A.L.T.A./N.S.P.S. Land Title Survey, City of Foothill Ranch, County of Orange, State of California, Job No. 5001-1056, 6 Sheets, dated February 3, 2025.

Petersen, M.D., Frankel, A.D., Harmsen, S.C., Mueller, C.S., Haller, K., Wheeler, R.L., Wesson, R.L., Zeng, Y., Boyd, O.S., Perkins, D.M., Luco, N., Field, E.H., Wills, C.J., and Rukstales, K.S., 2008, Documentation for the 2008 Update of the United States National Seismic Hazard Maps: U.S. Geological Survey (USGS), Open-File Report 2008–1128, 61p.

Portland Cement Association (PCA), 1984, Thickness Design for Concrete Highway and Street Pavements, Skokie, Illinois: Portland Cement Association.

Portland Cement Association, 1988. Design and Control of Concrete Mixtures, Portland Cement Association, Skokie, Illinois.

Pridmore, C.L., 2000, Liquefaction Zones in the El Toro 7.5-Minute Quadrangle, Orange County, California in Seismic Hazard Zone Report for the El Toro 7.5-Minute Quadrangle, Orange County, California: California Geological Survey Seismic Hazard Zone Report 047, pp. 3- 18.

Roberge, P., 2006, Corrosion Basics, 2nd ed.

Schoellhamer, J.E., Vedder, J.G., Yerkes, R.F., and Kinney, D.M., 1981, Geology of the Northern Santa Ana Mountains, California: U.S. Geologic Survey Professional Paper 420-D, 109p, 4 plates, Map Scale 1:24,000.

Singer, J.A. 1973, Geohydrology and artificial-recharge potential of the Irvine area, Orange County, California: U.S. Geological Survey Open File Report 73-264, 41p.

State of California, 2021, Tsunami Hazard Area Map, Orange County; produced by the California Geological Survey and the California Governor's Office of Emergency Services; dated 2021, displayed at multiple scales.

United States Geological Survey (USGS), 2025, Areas of Land Subsidence in California, website accessed February, 2025 at: Subsiding Areas in California | USGS California Water Science Center
United States Geological Survey (USGS), 1949, El Toro Quadrangle, Orange County, California:

7.5 Minute Series (Topographic) 1:24,000 scale.

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United States Geologic Survey (USGS) and California Geological Survey (CGS), Quaternary fault and fold database for the United States, accessed February 5, 2025 at https://www.usgs.gov/programs/earthquake-hazards/faults Item: 11
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FIGURES
Item: 11
1118
The information included on this graphic representation has been compiled from a variety of sources and is subject to change without notice. Kleinfelder makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a land survey product nor is it designed or intended as a construction design document. The use or misuse of the information contained on this graphic representation is at the sole risk of the party using or misusing the information. CAD FILE: C:\Users\DFahrney\OneDrive - Kleinfelder\CADD\25003229\25003229_Costco_Foothill-Ranch.dwg N
DRAWN BY:

PROJECT:

CHECKED BY:

REVISED:

DATE:

FIGURE SITE VICINITY MAP 25003229
DMF
HM
01/2025
- 1
2,000 1,000 0 2,000
APPROXIMATE SCALE (feet)
SOURCE: U.S.G.S. 7.5' topographic series, Lake Forest,
California quadrangle, dated 2022. PLOTTED: 4/4/2025 1:21 PM BY: dean fahrney SITE

PROPOSED COSTCO WHOLESALE WAREHOUSE
26602 TOWNE CENTRE DRIVE

FOOTHILL RANCH, CALIFORNIA
Item: 11
1119
© 2025 Microsoft Corporation © 2024 Maxar ©CNES (2024) Distribution Airbus DS B-1
B-21
B-5 B-22
B-6
B-24
B-4
B-14
B-11
B-13
B-15
B-12
B-20
B-19
B-26
B-25
B-28
B-16
B-17
B-18
B-27
B-23
B-8
B-2
B-3
B-10
B-9
B-7
INF-3
INF-1
A
C
B
C'
D'
B'
A'
D
INF-4
INF-2 CAD FILE: C:\Users\DFahrney\OneDrive - Kleinfelder\CADD\25003229\25003229_Costco_Foothill-Ranch.dwg LAYOUT: 2 PLOTTED: 4/4/2025 1:47 PM BY: dean fahrney The information included on this graphic representation has been compiled from a variety of sources and is subject to change without notice. Kleinfelder makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a land survey product nor is it designed or intended as a construction design document. The use or misuse of the information contained on this graphic representation is at the sole risk of the party using or misusing the information.

N
150 75 0 150
APPROXIMATE SCALE (feet)
FIGURE

DRAWN BY
DATE:

PROJECT:

CHECKED BY
REVISED:

EXPLORATION LOCATION MAP 25003229
DMF
HM
01/2025
-
PROPOSED COSTCO WHOLESALE WAREHOUSE 2
26602 TOWNE CENTRE DRIVE

FOOTHILL RANCH, CALIFORNIA

TOWNE CENTER DR

MARKET PL
FOOTHILL TRANSPORTATION CORRIDOR - 241

EXPLANATION
B-28 APPROXIMATE BORING LOCATION
INF-4 APPROXIMATE INFILTRATION TEST LOCATION

PROPOSED

RETAINING WALL
Item: 11
1120

ELEVATION ELEVATION
720
730
740
750
760
770
780
790
800
720
730
740
750
760
770
780
790
800
0+00 1+00 2+00 3+00 4+00 5+00 6+00 7+00 7+10

PROPOSED COSTCO
WHOLESALE WAREHOUSE A (FFE = 782.20 FEET) A'
B-1
(PROJ. 37' NE)
B-9
(PROJ. 48' SW)
B-10
(PROJ. 51' NE)
INF-3
(PROJ. 52' NE)
INF-4
(PROJ. 1' NE)
TD=49.5'
TD=20.5' TD=20'
TD=5'
TD=10'

EXISTING
GRADE

PROPOSED
GRADE

PROPOSED
FILL
INF-2
(PROJ. 83' NE)
TD=10'
BUILDING PAD: WITHIN 10 FT OF
PAD, AT LEAST 5 FEET BELOW
EXISITING OR 3 FEET BELOW

FOOTINGS, WHICHEVER IS DEEPER
PAVEMENT: PROOF-ROLL
EXPOSED SUBGRADE.

OVEREXCAVATE SOFT AND

YIELDING MATERIAL IF

ENCOUNTERED
RETAINING WALL: AT LEAST
2 FEET BELOW EXISITING OR
2 FEET BELOW FOOTINGS,

WHICHEVER IS DEEPER

CAPISTRANO

FORMATION

CAPISTRANO

FORMATION

CAPISTRANO

FORMATION

ARTIFICIAL
FILL
?
?
? ?
?
?
? CAD FILE: C:\Users\DFahrney\OneDrive - Kleinfelder\CADD\25003229\25003229_Costco_Foothill-Ranch.dwg LAYOUT: 3 PLOTTED: 4/4/2025 2:28 PM BY: dean fahrney The information included on this graphic representation has been compiled from a variety of sources and is subject to change without notice. Kleinfelder makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a land survey product nor is it designed or intended as a construction design document. The use or misuse of the information contained on this graphic representation is at the sole risk of the party using or misusing the information.

FIGURE

DRAWN BY
DATE:

PROJECT:

CHECKED BY
REVISED:

CROSS-SECTION A-A' 25003229
DMF
HM
01/2025
-
PROPOSED COSTCO WHOLESALE WAREHOUSE 3
26602 TOWNE CENTRE DRIVE

FOOTHILL RANCH, CALIFORNIA
VERTICAL SCALE: 1" = 10'
HORIZONTAL SCALE: 1" = 100'
0 0 100
10 B-36
(PROJ.15' N)

APPROXIMATE BORING ELEVATION

PROJECTION OF BORING IN FEET

APPROXIMATE TEST DEPTH AND LENGTH OF BORING

ARTIFICIAL FILL SILTY TO CLAYEY SAND WITH VARYING AMOUNTS OF GRAVEL

EXPLANATION
TD=11.5'
NOTE: REFER TO APPENDIX A FOR DETAILED LOGS
CAPISTRANO FORMATION HIGHLY WEATHERED SANDSTONE. EXCAVATES AS

POORLY TO WELL GRADED SAND AND SILTY SAND
Item: 11
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ELEVATION ELEVATION
720
730
740
750
760
770
780
790
800
720
730
740
750
760
770
780
790
800
0+00 1+00 2+00 3+00 4+00 5+00 6+00 7+00 7+70

PROPOSED COSTCO
WHOLESALE WAREHOUSE B (FFE = 782.20 FEET) B'
B-5
(PROJ. 11' SW) B-6
(PROJ. 53' NE) B-11
(PROJ. 19' SW)
B-13
(PROJ. 11' SW)
B-15
(PROJ. 20' SW) B-19
(PROJ. 74' SW) B-16
(PROJ. 106' NE) B-17
(PROJ. 70' NE)
TD=20.5'
TD=21' TD=20.5'
TD=21'
TD=49'
TD=11'
TD=10.5'
TD=10.5'

EXISTING
GRADE

PROPOSED
GRADE

PROPOSED
FILL
BUILDING PAD: WITHIN 10 FT OF
PAD, AT LEAST 5 FEET BELOW
EXISITING OR 3 FEET BELOW

FOOTINGS, WHICHEVER IS DEEPER
PAVEMENT: PROOF-ROLL
EXPOSED SUBGRADE.

OVEREXCAVATE SOFT AND

YIELDING MATERIAL IF

ENCOUNTERED

CAPISTRANO

FORMATION

CAPISTRANO

FORMATION

CAPISTRANO

FORMATION

ARTIFICIAL
FILL
?
?
?
?
?
?
?
?
? ? ?

PROPOSED
CUT CAD FILE: C:\Users\DFahrney\OneDrive - Kleinfelder\CADD\25003229\25003229_Costco_Foothill-Ranch.dwg LAYOUT: 4 PLOTTED: 4/4/2025 2:31 PM BY: dean fahrney The information included on this graphic representation has been compiled from a variety of sources and is subject to change without notice. Kleinfelder makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a land survey product nor is it designed or intended as a construction design document. The use or misuse of the information contained on this graphic representation is at the sole risk of the party using or misusing the information.

FIGURE

DRAWN BY
DATE:

PROJECT:

CHECKED BY
REVISED:

CROSS-SECTION B-B' 25003229
DMF
HM
01/2025
-
PROPOSED COSTCO WHOLESALE WAREHOUSE 4
26602 TOWNE CENTRE DRIVE

FOOTHILL RANCH, CALIFORNIA
VERTICAL SCALE: 1" = 10'
HORIZONTAL SCALE: 1" = 100'
0 0 100
10 B-36
(PROJ.15' N)

APPROXIMATE BORING ELEVATION

PROJECTION OF BORING IN FEET

APPROXIMATE TEST DEPTH AND LENGTH OF BORING

ARTIFICIAL FILL SILTY TO CLAYEY SAND WITH VARYING AMOUNTS OF GRAVEL

EXPLANATION
TD=11.5'
NOTE: REFER TO APPENDIX A FOR DETAILED LOGS
CAPISTRANO FORMATION HIGHLY WEATHERED SANDSTONE. EXCAVATES AS

POORLY TO WELL GRADED SAND AND SILTY SAND
Item: 11
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ELEVATION ELEVATION
720
730
740
750
760
770
780
790
800
720
730
740
750
760
770
780
790
800
0+00 1+00 2+00 3+00 4+00 5+00 6+00 7+00 8+00 9+00 9+90

PROPOSED COSTCO
WHOLESALE WAREHOUSE C (FFE = 782.20 FEET) C'
INF-1
(PROJ. 14' SE)
B-1
(PROJ. 15' SE)
B-2
(PROJ. 15' SE)
B-3
(PROJ. 4' SE)
B-4
(PROJ. 24' SE)
B-5
(PROJ. 22' NW)
B-22
(PROJ. 82' NW)
B-23
(PROJ. 38' SE)
TD=10.5'
TD=10.5'
TD=21'
TD=21' TD=21'
TD=20.5'
TD=5'
TD=49.5'

EXISTING
GRADE

PROPOSED

PROPOSED GRADE
FILL

PROPOSED
CUT
BUILDING PAD: WITHIN 10 FT OF
PAD, AT LEAST 5 FEET BELOW
EXISITING OR 3 FEET BELOW

FOOTINGS, WHICHEVER IS DEEPER
PAVEMENT: PROOF-ROLL
EXPOSED SUBGRADE.

OVEREXCAVATE SOFT AND

YIELDING MATERIAL IF

ENCOUNTERED

CAPISTRANO

FORMATION

CAPISTRANO

FORMATION

ARTIFICIAL
FILL

ARTIFICIAL
FILL
? ?
?
?
?
?
?
?
? CAD FILE: C:\Users\DFahrney\OneDrive - Kleinfelder\CADD\25003229\25003229_Costco_Foothill-Ranch.dwg LAYOUT: 5 PLOTTED: 4/4/2025 2:45 PM BY: dean fahrney The information included on this graphic representation has been compiled from a variety of sources and is subject to change without notice. Kleinfelder makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a land survey product nor is it designed or intended as a construction design document. The use or misuse of the information contained on this graphic representation is at the sole risk of the party using or misusing the information.

FIGURE

DRAWN BY
DATE:

PROJECT:

CHECKED BY
REVISED:

CROSS-SECTION C-C' 25003229
DMF
HM
01/2025
-
PROPOSED COSTCO WHOLESALE WAREHOUSE 5
26602 TOWNE CENTRE DRIVE

FOOTHILL RANCH, CALIFORNIA
VERTICAL SCALE: 1" = 10'
HORIZONTAL SCALE: 1" = 100'
0 0 100
10 B-36
(PROJ.15' N)

APPROXIMATE BORING ELEVATION

PROJECTION OF BORING IN FEET

APPROXIMATE TEST DEPTH AND LENGTH OF BORING

ARTIFICIAL FILL SILTY TO CLAYEY SAND WITH VARYING AMOUNTS OF GRAVEL

EXPLANATION
TD=11.5'
NOTE: REFER TO APPENDIX A FOR DETAILED LOGS
CAPISTRANO FORMATION HIGHLY WEATHERED SANDSTONE. EXCAVATES AS

POORLY TO WELL GRADED SAND AND SILTY SAND
Item: 11
1123

ELEVATION ELEVATION
720
730
740
750
760
770
780
790
800
720
730
740
750
760
770
780
790
800
0+00 1+00 2+00 3+00 4+00 5+00 6+00 7+00 8+00 9+00 9+60

PROPOSED COSTCO
WHOLESALE WAREHOUSE D (FFE = 782.20 FEET) D'
INF-3
(PROJ. 51' NW)
B-14
(PROJ. 0')
B-15
(PROJ. 32' NW)
B-20
(PROJ. 34' NW)
B-21
(PROJ. 89' SE)
TD=5'
TD=20.5'
TD=49'
TD=10.5' TD=11'

EXISTING
GRADE

PROPOSED

GRADE PROPOSED
FILL
BUILDING PAD: WITHIN 10 FT OF
PAD, AT LEAST 5 FEET BELOW
EXISITING OR 3 FEET BELOW

FOOTINGS, WHICHEVER IS DEEPER
PAVEMENT: PROOF-ROLL
EXPOSED SUBGRADE.

OVEREXCAVATE SOFT AND

YIELDING MATERIAL IF

ENCOUNTERED
RETAINING WALL: AT LEAST
2 FEET BELOW EXISITING OR
2 FEET BELOW FOOTINGS,

WHICHEVER IS DEEPER

CAPISTRANO

FORMATION

CAPISTRANO

FORMATION

ARTIFICIAL
FILL
?
?
?
?
?
? ? ? ? CAD FILE: C:\Users\DFahrney\OneDrive - Kleinfelder\CADD\25003229\25003229_Costco_Foothill-Ranch.dwg LAYOUT: 6 PLOTTED: 4/4/2025 11:52 AM BY: dean fahrney The information included on this graphic representation has been compiled from a variety of sources and is subject to change without notice. Kleinfelder makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a land survey product nor is it designed or intended as a construction design document. The use or misuse of the information contained on this graphic representation is at the sole risk of the party using or misusing the information.

FIGURE

DRAWN BY
DATE:

PROJECT:

CHECKED BY
REVISED:

CROSS-SECTION D-D' 25003229
DMF
HM
01/2025
-
PROPOSED COSTCO WHOLESALE WAREHOUSE 6
26602 TOWNE CENTRE DRIVE

FOOTHILL RANCH, CALIFORNIA
VERTICAL SCALE: 1" = 10'
HORIZONTAL SCALE: 1" = 100'
0 0 100
10 B-36
(PROJ.15' N)

APPROXIMATE BORING ELEVATION

PROJECTION OF BORING IN FEET

APPROXIMATE TEST DEPTH AND LENGTH OF BORING

ARTIFICIAL FILL SILTY TO CLAYEY SAND WITH VARYING AMOUNTS OF GRAVEL

EXPLANATION
TD=11.5'
NOTE: REFER TO APPENDIX A FOR DETAILED LOGS
CAPISTRANO FORMATION HIGHLY WEATHERED SANDSTONE. EXCAVATES AS

POORLY TO WELL GRADED SAND AND SILTY SAND
Item: 11
1124
25003229.001A/LH25R178197R April 4, 2025
© 2025 Kleinfelder (Revised November 21, 2025)

APPENDIX A

FIELD EXPLORATIONS
Item: 11
1125
25003229.001A/LH25R178197R Page A-1 April 4, 2025
© 2025 Kleinfelder (Revised November 21, 2025)

APPENDIX A

FIELD EXPLORATIONS

GENERAL
Subsurface conditions at the site were explored by drilling 28 borings. In addition, 4 borehole infiltration tests were performed. The borings and infiltration tests were drilled by 2R Drilling, Inc. using truck-mounted, hollow-stem-auger drilling equipment to depths of between approximately 5 and 49½ feet below the existing ground surface (bgs) in the warehouse building, and parking and drive areas. The approximate locations of the borings and infiltration tests are presented on Figure 2.

Prior to commencement of the fieldwork, Underground Service Alert (USA) was notified and various geophysical techniques were used at the exploration locations to identify potential conflicts with subsurface structures.

The boring and infiltration test logs are presented as Figures A-4 through A-37. An explanation to the logs is presented as Figures A-1 through A-3. The exploration logs describe the earth materials encountered, samples obtained and show field and laboratory tests performed. The logs also shows the location, boring number, drilling date and the name of the drilling subcontractor.

The borings were logged by a Kleinfelder engineer or geologist using the Unified Soil Classification System. The boundaries between soil types shown on the logs are approximate because the transition between different soil layers may be gradual. Bulk and drive samples of selected earth materials were obtained from the borings.

A modified-California sampler was used to obtain drive samples of the soil encountered. This sampler consists of a 3-inch O.D., 2.4-inch I.D. split barrel shaft that is pushed or driven a total of 18-inches into the soil at the bottom of the boring. The soil was retained in six 1-inch brass rings for laboratory testing. An additional 2 inches of soil from each drive remained in the cutting shoe and was usually discarded after visually classifying the soil. The sampler was driven using a 140-pound hammer falling 30 inches. The total number of blows required to drive the sampler the final 12 inches is termed blow count and is recorded on the Log of Boring.

Samples were also obtained using a Standard Penetration Sampler (SPT). This sampler consists of a 2-inch O.D., 1-inch I.D. split barrel shaft that is advanced into the soils at the bottom of the drill hole a total of 18 inches. The sampler was driven using a 140-pound hammer falling 30 inches. The total number of hammer blows required to drive the sampler the final 12 inches is Item: 11
1126
25003229.001A/LH25R178197R Page A-2 April 4, 2025
© 2025 Kleinfelder (Revised November 21, 2025)
termed the blow count (N) and is recorded on the Log of Boring. The procedures we employed in the field are generally consistent with those described in ASTM Standard Test Method D1586.

Bulk and grab samples of the near-surface soils were directly retrieved from the auger cuttings from the borings.

Item: 11
1127
A-1

FIGURE GRAPHICS KEY
Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
The report and graphics key are an integral part of these logs. All data and interpretations in this log are subject to the explanations and limitations stated in the report.

Solid lines separating strata on the logs represent approximate boundaries only, dashed lines are inferred or extrapolated boundaries.

Actual transitions may be gradual or differ from those represented.

No warranty is provided as to the continuity of soil or rock conditions between individual sample locations.

Logs represent general soil or rock conditions observed at the point of exploration on the date indicated.

In general, Unified Soil Classification System (ASTM D2488/D2487) designations presented on the logs were based on visual classification in the field and were modified where appropriate based on gradation and index property testing.

Fine grained soils that plot within the hatched area on the Plasticity Chart, and coarse grained soils with between 5% and 12% passing the No. 200 sieve require dual USCS symbols, ie., CL-ML, GW-GM, GP-GM, GW-GC, GP-GC, GC-GM, SW-SM, SP-SM, SW-SC, SP-SC, SC-SM.

If sampler is not able to be driven at least 6 inches then 50/X indicates number of blows required to drive the identified sampler X inches with a 140 pound hammer falling 30 inches.

ABBREVIATIONS
Cu - Coefficients of Uniformity
CC - Coefficients of Curvature
WOH - Weight of Hammer
WOR - Weight of Rod

REFERENCES

1. American Society for Testing and Materials (ASTM), 2011, ASTM D2487: Classification of Soils for Engineering Purposes (Unified Soil Classification System).

GRAVELS
WITH >
12%
FINES

SILTS AND CLAYS
(Liquid Limit
less than 50)

WELL-GRADED GRAVEL WITH SILT,

WELL-GRADED GRAVEL WITH SILT AND SAND

POORLY GRADED GRAVEL WITH CLAY (OR SILTY

CLAY), POORLY GRADED GRAVEL WITH CLAY AND
(OR SILTY CLAY AND SAND)

SILTY GRAVEL,

SILTY GRAVEL WITH SAND

CLAYEY GRAVEL,

CLAYEY GRAVEL WITH SAND

POORLY GRADED GRAVEL WITH SILT,

POORLY GRADED GRAVEL WITH SILT AND SAND
SP
CLEAN
SANDS
WITH
<5%
FINES

ML SILT, SILT WITH SAND, SILT WITH GRAVEL CL

ORGANIC CLAY, ORGANIC CLAY WITH SAND, ORGANIC CLAY WITH GRAVEL, ORGANIC SILT, ORGANIC SILT WITH SAND, ORGANIC SILT WITH GRAVEL

ORGANIC CLAY, ORGANIC CLAY WITH SAND, ORGANIC CLAY WITH GRAVEL, ORGANIC SILT, ORGANIC SILT WITH SAND, ORGANIC SILT WITH GRAVEL CL-ML

WELL-GRADED GRAVEL WITH CLAY (OR SILTY

CLAY), WELL-GRADED GRAVEL WITH CLAY AND

SAND (OR SILT CLAY AND SAND)

SILTY CLAY, SILTY CLAY WITH SAND, SILTY CLAY WITH GRAVEL ELASTIC SILT. ELASTIC SILT WITH SAND, ELASTIC SILT WITH GRAVEL

FAT CLAY, FAT CLAY WITH SAND, FAT CLAY WITH GRAVEL
OL
SANDS
WITH >
12%
FINES
CLEAN
GRAVEL
WITH
<5%
FINES

GRAVELS
WITH
5% TO
12%
FINES
SW
SW-SC
SW-SM
SC-SM
GP-GM

SILTY, CLAYEY GRAVEL

SILTY, CLAYEY GRAVEL WITH SAND

WELL-GRADED SAND,

WELL-GRADED SAND WITH GRAVEL

POORLY GRADED SAND,

POORLY GRADED SAND WITH GRAVEL

WELL-GRADED SAND WITH SILT,

WELL-GRADED SAND WITH SILT AND GRAVEL

POORLY GRADED SAND WITH SILT,

POORLY GRADED SAND WITH SILT AND GRAVEL

POORLY GRADED SAND WITH CLAY,

POORLY GRADED SAND WITH CLAY AND GRAVEL
(OR SILTY CLAY AND GRAVEL)

SILTY SAND,

SILTY SAND WITH GRAVEL
GP-GC
GC-GM

FINE GRAINED SOILS
(50% or more passes
the No. #200 sieve)

WELL-GRADED GRAVEL,

WELL-GRADED GRAVEL WITH SAND

POORLY GRADED GRAVEL,

POORLY GRADED GRAVEL WITH SAND

WELL-GRADED SAND WITH CLAY (OR SILTY CLAY),

WELL-GRADED SAND WITH CLAY AND GRAVEL
(OR SILTY CLAY AND GRAVEL)

CLAYEY SAND,

CLAYEY SAND WITH GRAVEL
COARSE GRAINED SOILS (More than 50% retained on No. 200 Sieve)

SILTY, CLAYEY SAND,

SILTY, CLAYEY SAND WITH GRAVEL

LEAN CLAY, LEAN CLAY WITH SAND, LEAN CLAY WITH GRAVEL

SILTS AND CLAYS
(Liquid Limit
50 or greater)
NOTE: USE MATERIAL DESCRIPTION ON THE LOG TO DEFINE A GRAPHIC THAT MAY NOT BE PROVIDED ON THIS LEGEND.

MH
CH
OH

BULK SAMPLE

CALIFORNIA SAMPLER
(3 in. (76.2 mm.) outer diameter)

GRAB SAMPLE

STANDARD PENETRATION SPLIT SPOON SAMPLER
(2 in. (50.8 mm.) outer diameter and 1-3/8 in. (34.9 mm.) inner diameter)
UNIFIED SOIL CLASSIFICATION SYSTEM1
SP-SM
SP-SC
SM
SC
SANDS
WITH
5% TO
12%
FINES
GM
GC
GW
GP
GW-GM
GW-GC
SANDS (50% or more of coarse fraction passes the No. 4 Sieve) GRAVELS (More than 50% of coarse fraction retained on No. 4 Sieve)

DRILLING METHOD/SAMPLER TYPE GRAPHICS
NOTES

GROUND WATER GRAPHICS

OBSERVED SEEPAGE
WATER LEVEL (level where first observed)
WATER LEVEL (additional levels after exploration)
WATER LEVEL (level after stabilizing period)
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_GEO_LEG1_GRAPHICS_KEY_W_USCS] PLOTTED: 02/13/2025 01:45 PM BY: DEdrees DATE:

CHECKED BY: H.M
DRAWN BY: D.E
25003229.001A
PROJECT NO.:

Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1128
SPT-N
(# blows / ft)
FIGURE
A-2

SOIL DESCRIPTION KEY
(For additional tables, see ASTM D2488)
Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
coarse
fine
Gravel
Same color and appearance throughout
Breaks along definite planes of fracture with
little resistance to fracturing.

Homogeneous

DESCRIPTION
Alternating layers of varying material or color with layers at least 1/4-in. (6mm) thick, note thickness.

Fissured
Slickensided Fracture planes appear polished or glossy, sometimes striated.

DESCRIPTION
Non-Plastic
Low
Dry
Wet
Visible free water,
usually soil is below
water table

FIELD TEST
Absence of
moisture, dusty,
dry to the touch
Sand
Fines

GRAIN SIZE
>12 in. (304.8 mm.)
3 - 12 in. (76.2 - 304.8 mm.)
3/4 -3 in. (19 - 76.2 mm.)

0.19 - 0.75 in. (4.8 - 19 mm.)
#10 - #4 0.079 - 0.19 in. (2 - 4.9 mm.)

APPARENT

DENSITY
30 - 50
10 - 30
4 - 10
Secondary
Constituent is
Coarse Grained
Term
of
Use
<5%
With
Modifier
5 to <15%
Secondary
Constituent is
Fine Grained
15%
Trace <15%
15 to <30%
30%
AMOUNT

CRITERIA
<500

0.5 PP <1
1 PP <2
2 PP <4
4 PP
Pocket Pen
(tsf)
PP < 0.25
Medium Stiff

0.25 PP <0.5

SPT - N
(# blows / ft)
medium

SIEVE SIZE

DESCRIPTION
Damp but no
visible water
#40 - #10

0.0029 - 0.017 in. (0.07 - 0.43 mm.)
Passing #200 <0.0029 in. (<0.07 mm.)

DESCRIPTION
3 - 12 in.
3/4 -3 in.
#4 - 3/4 in.
1,000 - 2,000
2,000 - 4,000
4,000 - 8,000
>8,000
<4
Very Dense
Dense
Medium Dense
>50
Loose
Very Loose
Alternating layers of varying material or color with the layers less than 1/4-in. (6 mm) thick, note thickness. Laminated Inclusion of small pockets of different soils, such as small lenses of sand scattered through a mass of clay; note thickness. Lensed Boulders
Cobbles

0.017 - 0.079 in. (0.43 - 2 mm.)
#200 - #40
Cohesive soil that can be broken down into small angular lumps which resist further breakdown. Blocky

CRITERIA
Medium
High

CRITERIA
A 1/8 in. (3 mm) thread cannot be rolled at any water content.

The thread can barely be rolled and the lump cannot be formed when drier than the plastic limit.

The thread is easy to roll and not much time is required to reach the plastic limit. The thread cannot be rerolled after reaching the plastic limit. The lump crumbles when drier than the plastic limit.

It takes considerable time rolling and kneading to reach the plastic limit. The thread can be rerolled several times after reaching the plastic limit. The lump can be formed without crumbling when drier than the plastic limit.
coarse
fine
Moist
Rounded
Subrounded Particles have nearly plane sides but have well-rounded corners and edges.

Angular Particles have sharp edges and relatively plane sides with unpolished surfaces.

Subangular
Particles have smoothly curved sides and no edges.

Particles are similar to angular description but have rounded edges.

DESCRIPTION
None
Weak
Crumbles or breaks
with considerable finger
pressure
Moderately
Weakly
Will not crumble or
break with finger
pressure

DESCRIPTION
Strongly

FIELD TEST
Crumbles or breaks
with handling or little
finger pressure
Readily indented by thumb but penetrated only
with great effort
Easily penetrated several inches by fist
Easily penetrated several inches by thumb
Can be penetrated several inches by thumb with
moderate effort
Readily indented by thumbnail
Indented by thumbnail with difficulty

CONSISTENCY VISUAL / MANUAL CRITERIA
<2
>30
Very Soft
Strong
No visible reaction
Some reaction,
with bubbles
forming slowly
Violent reaction,
with bubbles
forming
immediately

DESCRIPTION FIELD TEST
Soft
Stiff
Very Stiff
Hard
2 - 4
4 - 8
8 - 15
15 - 30

UNCONFINED

COMPRESSIVE
STRENGTH (Qu)(psf)
>12 in.

Stratified
500 - 1,000
STRUCTURE1 ANGULARITY1
GRAIN SIZE1
CONSISTENCY - FINE-GRAINED SOIL2, 3
CEMENTATION1

APPARENT DENSITY -
COARSE-GRAINED SOIL2
PLASTICITY1 MOISTURE CONTENT1

REACTION WITH
HYDROCHLORIC ACID1
SECONDARY CONSTITUENT1

REFERENCES

1. American Society for Materials and Testing (ASTM), 2017, ASTM D2488: Standard Practice for Description and Identification of Soils (Visual Manual Procedures).

2. Terzaghi, K and Peck, R., 1948, Soil Mechanics in Engineering Practice, John Wiley & Sons, New York.

3. United States Department of the Interior Bureau of Reclamation (USBR), 1998, Earth Manual, Part I.
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [_KLF_GEO_LEG2_SOIL_DESC_KEY] PLOTTED: 02/13/2025 01:47 PM BY: DEdrees DATE:

CHECKED BY: H.M
DRAWN BY: D.E
25003229.001A
PROJECT NO.:

Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1129
A-3

ROCK DESCRIPTION KEY FIGURE
Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
Slightly Fractured
Moderately Fractured
Highly Fractured

RECOGNITION
Honeycombed
Small openings in volcanic rocks
of variable shape and size formed
by entrapped gas bubbles during
solidification.

Vesicle (Vesicular)
Pit (Pitted)
None
Muscovite
Small openings (usually lined with
crystals) ranging in diameter from

0.03 ft. (3/8 in.) to 0.33 ft. (4 in.)
(10 to 100 mm.)
RQD
Bedding Planes
Fracture in rock, generally more or
less vertical or traverse to bedding.

Planes dividing the individual layers,
beds, or stratigraphy of rocks.

DESCRIPTION Thickness [in (mm)]
>36 (>915)
12 - 36 (305 - 915)
4 - 12 (102 - 305)
1 - 4 (25 - 102)

0.4 - 1 (10 - 25)

0.1 - 0.4 (2.5 - 10)
<0.1 (<2.5)
Extremely Weak
Very Weak
Weak
Medium Strong

0.25 - 1.0

1.0 - 5.0

FIELD TEST
Specimen can only be chipped with a geological hammer.

Specimen requires many blows of geological
hammer to fracture it.

Cannot be scraped or peeled with a pocket knife, specimen can be fractured with a single firm blow of a geological hammer.

Albite
Biotite
Manganese Mn
Unweathered
Entire mass discolored; Alteration
pervading most rock, some slight
weathering pockets; some
minerals may be leached out.

Tight
Open
Wide

DESCRIPTION

0.04 - 0.20 (1 - 5)
>0.20 (>5)
<0.04 (<1)
CRITERIA [in (mm)]
>6 ft. (>1.83 meters)
2 - 6 ft. (0.061 - 1.83 meters)
8 in - 2 ft. (203.20 - 609.60 mm)
Rock-quality designation (RQD) Rough measure of
the degree of jointing or fracture in a rock mass,
measured as a percentage of the drill core in lengths
of 4 in. (10 cm.) or more.
2 - 8 in (50.80 - 203.30 mm)
Joint
Seam
Intensely Fractured

SPACING CRITERIA
<2 in (<50.80 mm)

DESCRIPTION
Unfractured
Applies to bedding plane with
unspecified degree of weather.

Pinhole to 0.03 ft. (3/8 in.) (>1 to
10 mm.) openings
Vug (Vuggy)

DESCRIPTION
An opening larger than 0.33 ft. (4
in.) (100 mm.), size descriptions
are required, and adjectives such
as small, large, etc., may be used
Cavity
If numerous enough that only thin
walls separate individual pits or
vugs, this term further describes
the preceding nomenclature to
indicate cell-like form.

CRITERIA
Discoloring evident; surface pitted
and alteration penetration well
below surface; Weathering "halos"
evident; 10-50% rock altered.

No evidence of chemical /
mechanical alternation; rings with
hammer blow.

Rock reduced to soil with relic
rock texture/structure; Generally
molded and crumbled by hand.

Moderately Weathered
Slightly Weathered

DESCRIPTION
ABBR
Uk
Ta
Si
Ser
Sd
NAME
Very Thick Bedded
Epidote Ep
Ch
Ca
Cl
Ap
Strong
Very Strong
Extremely Strong

5.0 - 25
25 - 50
50 - 100
Iron Oxide Fe
Gypsum Gy
100 - 250
> 250
GRADE
Indented by thumbnail
Apatite
Clay
Calcite
Chlorite
ABBR
Bi
NAME
Unknown
Talc
Silt
Moderately Bedded
Thin Bedded
Laminated
Thinly Laminated
Sericite
Sand
Quartz
Pyrite
Qz
Py
No
Mus
Crumbles under firm blows of geological hammer,
can be peeled by a pocket knife.

Specimen requires more than one blow of geological hammer to fracture it.

Al R0
R1
R2
R3
R4
R5
R6
Poor
Very Poor
RQD (%)
Thick Bedded
Very Thin Bedded
Can be peeled by a pocket knife with difficulty, shallow indentations made by firm blow with point of geological hammer.
0 - 25
25 - 50
50 - 75
75 - 90
90 - 100
Fair
Good
Excellent

DESCRIPTION
Decomposed
Highly Weathered
Slight discoloration on surface;
slight alteration along
discontinuities; <10% rock volume
altered.

CORE SAMPLER

AQ CORE BARREL
(1.067 in. (27.1 mm.) core diameter)

AX CORE BARREL
(1.185 in. (30.1 mm.) core diameter)

BQ CORE BARREL
(1.433 in. (36.4 mm.) core diameter)

CONTINUOUS CORE SAMPLE
(2.000 in. (50.8 mm.) core diameter)

CORE SAMPLER TYPE GRAPHICS

EX CORE BARREL
(0.846 in. (21.5 mm.) core diameter)

HQ CORE SAMPLE
(2.500 in. (63.5 mm.) core diameter)

NQ CORE SAMPLE
(1.874 in. (47.6 mm.) core diameter)

NO RECOVERY CORE SAMPLE

NX CORE SAMPLE
(2.154 in. (54.7 mm.) core diameter)

REFERENCES

1. Bieniawski, Z.T., 1989, Engineering Rock Mass
Classifications. John Wiley & Sons, New York. (Mod. by
Kleinfelder).

2. Deere, D.U., and Deere, D.W., 1989, Rock Quality
Designation (RQD) After Twenty Years, USACE Contract
Report GL-89-1.

3. Federal Highway Administration (FHWA), 2002,
Subsurface Investigations, FHWA-NHI-01-031. (Mod. by
Kleinfelder).

4. International Society for Rock Mechanics (ISRM), 1978, "Suggested Methods for the Quantitative Description of
Discontinuities in Rock Masses," International Joint Rock Mechanics and Mining Sciences & Geomechanics Abstracts, Vol. 15. 5. United States Army Corps of Engineers (USACE), 1994, Rock Foundations, EM 1110-1-2908, November 30, 1994.

6. United States Department of the Interior Bureau of
Reclamation (USBR), 1998, Engineering Geology Field
Manual, Volume 1.

UCS (MPa)
4 - 6
6 - 8
2 - 4
8 - 10
10 cm
0 - 2
12 - 14
18 - 20
14 - 16
16 - 18
WEATHERING5
ADDITIONAL TEXTURAL ADJECTIVES5
DENSITY/SPACING OF DISCONTINUITIES5
INFILLING TYPE3
5 cm0
RELATIVE HARDNESS / STRENGTH DESCRIPTIONS4
ROCK QUALITY DESIGNATION (RQD)2 JOINT ROUGHNESS COEFFICIENT (JRC)4 APERTURE1
BEDDING CHARACTERISTICS6
10 - 12
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [_KLF_GEO_LEG3_ROCK_DESC_KEY] PLOTTED: 02/13/2025 01:47 PM BY: DEdrees DATE:

CHECKED BY: H.M
DRAWN BY: D.E
25003229.001A
PROJECT NO.:

Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1130
113.8
109.8
Asphalt: approximately 3.5"
Aggregate Base: approximately 5"
Artificial Fill
Silty SAND (SM): fine to medium sand, low
plasticity, brown, moist
light gray, loose
medium dense
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
light gray, fine to medium sand, moist, highly
weathered, very weak (R1)
light olive gray, decrease in fines
light gray
olive gray
excavates as clayey sand (SC), olive-light
brown, fine to medium sand, low plasticity
18"
18"
10"
10"
2"
10"
3"

9.8 11.6

9.0 8.6
BC=9
9 6
BC=10
12 14
BC=24
50/4"
BC=23
50/4"
BC=50/2"
BC=20
50/4"
BC=50/3"
30 Hand auger 5ft bgs
5 1 of 2

FIELD EXPLORATION
A-1

LABORATORY RESULTS
Lithologic Description
BORING LOG B-1
PAGE:

BORING LOG B-1
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67737°
Longitude: -117.67003°
Ground Surface Elevation (ft.): 781.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Windy Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/13/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
780
775
770
765
760
755
750
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
5 6
7 PLOTTED: 02/14/2025 11:47 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1131
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
light gray, fine to medium sand, moist, trace
clay, trace subangular gravel, highly
weathered, very weak (R1)
fine to coarse sand
excavates as poorly graded sand with silt
(SP-SM), light gray, fine to medium sand
The boring was terminated at approximately

49.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 13, 2025.
6"
4"
6"
12"
BC=50/6"
BC=50/4"
BC=50/6"
BC=32
50/6"
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
2 of 2

FIELD EXPLORATION
A-2

LABORATORY RESULTS
Lithologic Description
BORING LOG B-1
PAGE:

BORING LOG B-1
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67737°
Longitude: -117.67003°
Ground Surface Elevation (ft.): 781.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Windy Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/13/2025
Depth (feet)
40 45
50 55
60 65
Elevation (feet)
745
740
735
730
725
720
715
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
8 9
10 11
PLOTTED: 02/14/2025 11:47 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1132
116.7
119.7
21 Asphalt: approximately 4"
Aggregate Base: approximately 4"
Artifical Fill
Clayey SAND (SC): fine to medium sand,
light brown, moist, trace fine anglar gravel
Silty SAND (SM): fine to medium sand,
non-plastic to low plasticity, light gray, moist,
trace clay
medium dense
Clayey SAND (SC): fine to medium sand,
olive gray, moist, trace coarse sand
medium dense
Capistrano Formation
SANDSTONE: excavates as silty clayey sand
(SC-SM), light gray, fine to medium sand,
moist, trace gravel, highly weathered, very
weak (R1)
excavates as silty sand (SM), light gray, fine to
coarse sand
The boring was terminated at approximately
21 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 13, 2025.
18"
18"
18"
18"
12"

9.4 12.0

14.8 13.1

11.6 BC=5
8 9
BC=10
17 22
BC=8
14 14
BC=8
15 21
BC=26
50/6"
Hand auger 5ft bgs
Corrosion Test
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-3

LABORATORY RESULTS
Lithologic Description
BORING LOG B-2
PAGE:

BORING LOG B-2
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67753°
Longitude: -117.66967°
Ground Surface Elevation (ft.): 782.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Windy Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/13/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
780
775
770
765
760
755
750
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
5 6
PLOTTED: 02/14/2025 11:48 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1133
117.8
120.9
Asphalt: approximately 4"
Aggregate Base: approximately 3"
Artificial Fill
Clayey SAND (SC): fine to medium sand, low
plasticity, brown, moist
medium dense
Silty SAND (SM): fine to medium sand, light
gray, moist
non-plastic to low plasticity
medium dense
Capistrano Formation
SANDSTONE: fine to medium sand,
excavates as silty sand (SM), light gray, fine to
coarse sand, moist, highly weathered, very
weak (R1)
olive-light gray, fine to medium sand
The boring was terminated at approximately
21 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 13, 2025.
18"
18"
18"
18"
9"

11.8 12.0

10.8 10.6
BC=12
18 14
BC=7
10 9
BC=11
17 20
BC=15
26 50
BC=40
50/3"
29 Hand auger 5ft bgs
3 Groundwater was not observed during drilling or after completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-4

LABORATORY RESULTS
Lithologic Description
BORING LOG B-3
PAGE:

BORING LOG B-3
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67768°
Longitude: -117.66928°
Ground Surface Elevation (ft.): 783.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Windy Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/13/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
780
775
770
765
760
755
750
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
5 PLOTTED: 02/14/2025 11:48 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1134
112.2
16 Asphalt: approximately 3"
Aggregate Base: approximately 6"
Artificial Fill
Silty SAND (SM): fine to medium sand,
brown, moist, trace clay, tree branches
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
light gray, fine to medium sand, moist, highly
weathered, very weak (R1)
trace coarse sand
fine to coarse sand
increase in fines, fine to medium sand
The boring was terminated at approximately
21 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 16, 2025.
10"
3"
3"
6"
10"

8.1 7.3
BC=19
50/4"
BC=50/3"
BC=50/3"
BC=50/6"
BC=39
50/4"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-5

LABORATORY RESULTS
Lithologic Description
BORING LOG B-4
PAGE:

BORING LOG B-4
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67789°
Longitude: -117.66894°
Ground Surface Elevation (ft.): 784.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/16/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
780
775
770
765
760
755
750
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
5 PLOTTED: 02/14/2025 11:48 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1135
125.9
102.6
Asphalt: approximately 3"
Aggregate Base: approximately 5"
Artificial Fill
Clayey SAND (SC): fine to medium sand, low
plasticity, brown, moist, trace coarse sand
Silty SAND (SM): fine to medium sand,
non-plastic to low plasticity, olive gray, moist
dense
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
light gray, fine to medium sand, moist, highly
weathered, very weak (R1)
excavates as poorly graded sand (SP)
excavates as silty sand (SM)
increase in fines, trace coarse sand
The boring was terminated at approximately

20.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 16, 2025.
18"
17"
5"
11"
4"

11.0 11.7

13.4 BC=13
21 31
BC=35
35 50/5"
BC=50/5"
BC=31
50/5"
BC=50/4"
25 Hand auger 5ft bgs
3 Groundwater was not observed during drilling or after completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-6

LABORATORY RESULTS
Lithologic Description
BORING LOG B-5
PAGE:

BORING LOG B-5
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67792°
Longitude: -117.66856°
Ground Surface Elevation (ft.): 782.5
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/16/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
780
775
770
765
760
755
750
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
5 PLOTTED: 02/14/2025 11:48 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1136
140.0
Asphalt: approximately 3"
Aggregate Base: approximately 6"
Artificial Fill
Clayey SAND (SC): fine to medium sand, low
plasticity, brown, moist
Capistrano Formation
SANDSTONE: excavates as poorly graded
sand (SP), gray, fine to coarse sand, moist,
highly weathered, very weak (R1)
excavates as silty sand (SM), light gray, fine
to medium sand
excavates as clayey sand (SC), olive gray
excavates as poorly graded sand with silt
(SP-SM), gray
The boring was terminated at approximately
21 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 15, 2025.
18"
3"
9"
5"
9"

13.6 2.0

10.9 BC=6
6 7
BC=50/3"
BC=33
50/3"
BC=50/5"
BC=37
50/3"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-7

LABORATORY RESULTS
Lithologic Description
BORING LOG B-6
PAGE:

BORING LOG B-6
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67768°
Longitude: -117.66864°
Ground Surface Elevation (ft.): 781.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/15/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
780
775
770
765
760
755
750
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
5 PLOTTED: 02/14/2025 11:48 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1137
123.5
111.4
19 Asphalt: approximately 4"
Aggregate Base: approximately 6"
Artificial Fill
Clayey SAND (SC): fine to medium sand, low
plasticity, grayish brown, moist, trace gravel
up to 0.75"
Silty SAND (SM): fine to medium sand,
non-plastic, olive gray, moist, trace coarse
sand
dense
light gray
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
light gray, fine sand, moist, highly weathered,
very weak (R1)
excavates as poorly graded sand with silt
(SP-SM), fine to medium sand
fine to coarse sand
The boring was terminated at approximately

20.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 16, 2025.
18"
18"
11"
11"
5"

10.9 11.7

12.6 9.4
BC=15
21 25
BC=7
13 27
BC=26
50/5"
BC=29
50/5"
BC=50/5"
NP
Hand auger 5ft bgs
NP
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-8

LABORATORY RESULTS
Lithologic Description
BORING LOG B-7
PAGE:

BORING LOG B-7
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67754°
Longitude: -117.66888°
Ground Surface Elevation (ft.): 780.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/16/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
5 PLOTTED: 02/14/2025 11:48 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1138
120.6
110.4
Asphalt: approximately 4"
Aggregate Base: approximately 6"
Artificial Fill
Clayey SAND with Gravel (SC): fine to
medium sand, low plasticity, brown, moist,
angular to subangular gravel up to 0.5"
Silty SAND (SM): fine to medium sand, olive,
moist
medium dense
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
fine sand, light gray, highly weathered, very
weak (R1)
fine to medium sand
trace coarse sand
excavates as poorly graded sand with silt
(SP-SM), fine to medium sand, subangular
gravel up 0.5"
The boring was terminated at approximately

20.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 13, 2025.
18"
11"
9"
11"
5"

12.8 8.7

7.9 8.0
BC=18
17 23
BC=17
50/5"
BC=45
50/3"
BC=32
50/5"
BC=50/5"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-9

LABORATORY RESULTS
Lithologic Description
BORING LOG B-8
PAGE:

BORING LOG B-8
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67740°
Longitude: -117.66930°
Ground Surface Elevation (ft.): 779.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Windy Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/13/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
745
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
5 PLOTTED: 02/14/2025 11:48 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1139
115.3
107.8
16 Asphalt: approximately 4"
Aggregate Base: approximately 3"
Artificial Fill
Silty SAND (SM): fine to medium sand, olive
brown, moist
olive to light brown, medium dense
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
light gray, fine to medium sand, moist, highly
weathered, very weak (R1)
fine sand
excavates as poorly graded sand (SP-SM),
fine to medium sand
The boring was terminated at approximately

20.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 13, 2025.
18"
9"
10"
4"
6"

10.1 7.9

7.9 6.7
BC=8
9 9
BC=28
50/3"
BC=40
50/4"
BC=50/4"
BC=50/6"
27 Hand auger 5ft bgs
5 Groundwater was not observed during drilling or after completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-10

LABORATORY RESULTS
Lithologic Description
BORING LOG B-9
PAGE:

BORING LOG B-9
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67724°
Longitude: -117.66964°
Ground Surface Elevation (ft.): 778.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Windy Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/13/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
745
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
5 PLOTTED: 02/14/2025 11:48 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1140
126.6
115.6
Asphalt: approximately 4"
Aggregate Base: approximately 3"
Artificial Fill
Silty SAND (SM): fine to medium sand, olive
brown, moist
light gray, dense
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
light gray, fine sand, moist, highly weathered,
very weak (R1)
fine to medium sand
The boring was terminated at approximately
20 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 13, 2025.
18"
11"
9"
11"
2"

10.9 8.6

8.9 7.6
BC=12
19 48
BC=38
50/5"
BC=50/6"
BC=50/6"
BC=50/2"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-11

LABORATORY RESULTS
Lithologic Description
BORING LOG B-10
PAGE:

BORING LOG B-10
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67706°
Longitude: -117.66989°
Ground Surface Elevation (ft.): 777.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Windy Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/13/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
745
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
5 PLOTTED: 02/14/2025 11:49 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1141
123.6
108.7
17 Asphalt: approximately 4"
Aggregate Base: approximately 5"
Artificial Fill
Clayey SAND (SC): fine to medium sand,
non-plastic to low plasticity, brown, moist,
trace subrounded gravel
Silty SAND (SM): fine to medium sand, olive
gray, moist, trace clay
medium dense
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
olive gray, fine to medium sand, moist, highly
weathered, very weak (R1)
gray, decrease in fines
excavates as poorly graded sand (SP)
olive gray
The boring was terminated at approximately

20.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 15, 2025.
18"
11"
5"
3"
5"

12.1 12.4

9.2 9.3
BC=20
15 22
BC=28
50/5"
BC=50/5"
BC=50/3"
BC=50/5"
Hand auger 5ft bgs
Corrosion Test
Modified Proctor
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-12

LABORATORY RESULTS
Lithologic Description
BORING LOG B-11
PAGE:

BORING LOG B-11
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67763°
Longitude: -117.66833°
Ground Surface Elevation (ft.): 781.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/15/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
780
775
770
765
760
755
750
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
5 6
PLOTTED: 02/14/2025 11:49 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1142
124.0
108.7
Asphalt: approximately 2.5"
Aggregate Base: approximately 6"
Artificial Fill
Silty SAND (SM): fine to medium sand,
brown, moist
gray
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
light gray, fine to medium sand, moist, highly
weathered, very weak (R1)
excavates as poorly graded sand with silt
(SP-SM)
excavates as silty sand (SM)
increase in sand, trace coarse sand
The boring was terminated at approximately

20.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 15, 2025.
18"
11"
6"
6"
4"

13.0 9.9

9.8 8.7
BC=8
16 33
BC=33
50/5"
BC=50/6"
BC=50/6"
BC=50/4"
NP
Hand auger 5ft bgs
NP
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-13

LABORATORY RESULTS
Lithologic Description
BORING LOG B-12
PAGE:

BORING LOG B-12
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67733°
Longitude: -117.66861°
Ground Surface Elevation (ft.): 778.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/15/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
745
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
5 PLOTTED: 02/14/2025 11:49 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1143
123.8
Asphalt: approximately 3.5"
Aggregate Base: approximately 6"
Artificial Fill
Clayey SAND (SC): fine to medium sand,
brown, moist, trace subangular gravel up to

0.5"
Silty SAND (SM): fine to medium sand, light
gray, moist
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
light gray, fine to medium sand, moist, highly
weathered, very weak (R1)
trace clay
decrease in fines, trace coarse sand
increase in fines, fine to coarse sand
olive gray, increase in fines, fine sand
The boring was terminated at approximately
21 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 15, 2025.
18"
5"
7"
9"
12"

10.3 9.7

8.2 BC=8
18 40
BC=50/5"
BC=37
50/1"
BC=26
50/3"
BC=25
50/6"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-14

LABORATORY RESULTS
Lithologic Description
BORING LOG B-13
PAGE:

BORING LOG B-13
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67742°
Longitude: -117.66823°
Ground Surface Elevation (ft.): 780.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/15/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
5 PLOTTED: 02/14/2025 11:49 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1144
121.4
116.8
15 Asphalt: approximately 4"
Aggregate Base: approximately 6"
Artificial Fill
Clayey SAND (SC): fine to medium sand, low
plasticity, brown, moist
olive gray, medium dense
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
light gray, fine to medium sand, moist, highly
weathered, very weak (R1)
decrease in fines
excavates as silty clayey sand (SC-SM),
non-plastic to low plasticity
excavates as silty sand (SM)
The boring was terminated at approximately

20.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 15, 2025.
18"
12"
3"
3"
6"

13.9 13.5

7.8 4.3
BC=4
5 9
BC=13
50/6"
BC=50/3"
BC=50/3"
BC=50/6"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-15

LABORATORY RESULTS
Lithologic Description
BORING LOG B-14
PAGE:

BORING LOG B-14
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67711°
Longitude: -117.66847°
Ground Surface Elevation (ft.): 777.5
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/15/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
745
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
5 PLOTTED: 02/14/2025 11:49 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1145
121.3
116.3
Asphalt: approximately 2.5"
Aggregate Base: approximately 3"
Artificial Fill
Silty SAND (SM): fine to medium sand,
brown, moist
olive gray, medium dense, increase in fines
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
olive gray, fine to medium sand, moist, highly
weathered, very weak (R1)
excavates as pooly graded sand with silt
(SP-SM), light gray
excavates as pooly graded sand (SP)
excavates as silty sand (SM)
excavates as pooly graded sand with silt
(SP-SM), light gray
18"
6"
6"
10"
4"
3"
6"

12.4 7.9

9.8 10.8
BC=25
18 19
BC=50/6"
BC=50/6"
BC=30
50/4"
BC=50/4"
BC=50/3"
BC=50/6"
NP
Hand auger 5ft bgs
NP
1 of 2

FIELD EXPLORATION
A-16

LABORATORY RESULTS
Lithologic Description
BORING LOG B-15
PAGE:

BORING LOG B-15
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67720°
Longitude: -117.66806°
Ground Surface Elevation (ft.): 779.5
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/15/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
745
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
5 6
7 PLOTTED: 02/14/2025 11:49 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1146
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
olive gray, fine to medium sand, moist, highly
weathered, very weak (R1)
excavates as silty sand (SM), fine sand
excavates as pooly graded sand (SP), light
gray
The boring was terminated at approximately
49 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 15, 2025.
6"
4"
6"
4"
BC=50/6"
BC=50/4"
BC=50/6"
BC=50/4"
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
2 of 2

FIELD EXPLORATION
A-17

LABORATORY RESULTS
Lithologic Description
BORING LOG B-15
PAGE:

BORING LOG B-15
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67720°
Longitude: -117.66806°
Ground Surface Elevation (ft.): 779.5
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/15/2025
Depth (feet)
40 45
50 55
60 65
Elevation (feet)
740
735
730
725
720
715
710
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
8 9
10 11
PLOTTED: 02/14/2025 11:49 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1147
125.1
115.7
14 Asphalt: approximately 3"
Aggregate Base: approximately 5"
Artificial Fill
Clayey SAND (SC): fine to medium sand, low
plasticity, brown, moist
Silty SAND (SM): fine to medium sand, olive
gray, moist, trace clay
dense
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
light gray, fine to medium sand, moist. highly
weathered, very weak (R1)
decrease in fines
excavates as poorly graded sand with silt
(SP-SM)
The boring was terminated at approximately

10.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 14, 2025.
18"
12"
6"

10.1 11.0

9.0 8.9
BC=10
20 36
BC=32
50/6"
BC=50/6"
Hand auger 5ft bgs
Corrosion Test
Modified Proctor
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-18

LABORATORY RESULTS
Lithologic Description
BORING LOG B-16
PAGE:

BORING LOG B-16
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67661°
Longitude: -117.66814°
Ground Surface Elevation (ft.): 776.5
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/14/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
745
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
PLOTTED: 02/14/2025 11:49 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1148
122.6
109.0
22 Asphalt: approximately 3"
Aggregate Base: approximately 5"
Artificial Fill
Clayey SAND with Gravel (SC): fine to
medium sand, brown, moist, angular to
subangular gravel up to 0.5"
Capistrano Formation
SANDSTONE: excavates as sity sand (SM),
light gray, fine to medium sand, highly
weathered, very weak (R1)
trace clay
excavates as clayey sand (SC), low plasticity
The boring was terminated at approximately

10.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 14, 2025.
17"
16"
6"

13.6 10.3

19.7 BC=10
36 50/5"
BC=25
36 50/4"
BC=50/6"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-19

LABORATORY RESULTS
Lithologic Description
BORING LOG B-17
PAGE:

BORING LOG B-17
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67632°
Longitude: -117.66782°
Ground Surface Elevation (ft.): 775.5
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/14/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
745
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 PLOTTED: 02/14/2025 11:49 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1149
114.7
Asphalt: approximately 3.5"
Aggregate Base: approximately 4"
Artificial Fill
Clayey SAND (SC): fine to medium sand,
brown, moist
Silty SAND (SM): fine to coarse sand, gray,
moist
fine to medium sand
Capistrano Formation
SANDSTONE: excavates as poorly graded
sand (SP-SM), light gray, fine to medium
sand, highly weathered, very weak (R1)
excavates as sity sand (SM)
The boring was terminated at approximately

10.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 14, 2025.
18"
6"
6"

11.7 9.3

9.1 BC=16
24 44
BC=50/6"
BC=50/6"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-20

LABORATORY RESULTS
Lithologic Description
BORING LOG B-18
PAGE:

BORING LOG B-18
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67659°
Longitude: -117.66719°
Ground Surface Elevation (ft.): 776.5
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/14/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
745
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 PLOTTED: 02/14/2025 11:49 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1150
121.9
Asphalt: approximately 3.5"
Aggregate Base: approximately 5"
Artificial Fill
Silty Clayey SAND (SC-SM): fine to medium
sand, brown, moist, trace angular fine gravel
Silty SAND (SM): fine sand, light gray, moist
dense
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
light gray, fine to medium sand, moist, highly
weathered, very weak (R1)
The boring was terminated at approximately
11 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 14, 2025.
18"
6"
12"

12.9 10.8

10.6 BC=7
14 23
BC=50/6"
BC=31
50/6"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-21

LABORATORY RESULTS
Lithologic Description
BORING LOG B-19
PAGE:

BORING LOG B-19
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67708°
Longitude: -117.66777°
Ground Surface Elevation (ft.): 780.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/14/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 PLOTTED: 02/14/2025 11:50 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1151
122.0
22 Asphalt: approximately 3.5"
Aggregate Base: approximately 5"
Artificial Fill
Clayey SAND (SC): fine to medium sand, low
plasticity, olive gray, moist
Silty SAND (SM): fine to medium sand, olive
gray, moist
Capistrano Formation
SANDSTONE (SM): light gray, moist,
excavates as silty sand (SM), light gray, fine to
coarse sand, highly weathered, very weak
(R1)
excavates as poorly graded sand (SP)
The boring was terminated at approximately

10.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 15, 2025.
18"
6"
5"

9.6 16.3

10.6 8.7
BC=4
5 15
BC=50/6"
BC=50/5"
30 Hand auger 5ft bgs
8 R-Value Test
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-22

LABORATORY RESULTS
Lithologic Description
BORING LOG B-20
PAGE:

BORING LOG B-20
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67742°
Longitude: -117.66756°
Ground Surface Elevation (ft.): 782.5
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/15/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
780
775
770
765
760
755
750
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
PLOTTED: 02/14/2025 11:50 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1152
18 Asphalt: approximately 3"
Aggregate Base: approximately 5"
Artificial Fill
Clayey SAND (SC): fine to medium sand, low
plasticity, brown, moist
Capistrano Formation
SANDSTONE: excavates as clayey sand
(SC), light gray, fine to medium sand, moist,
highly weathered, very weak (R1)
excavates as silty sand (SM), olive
The boring was terminated at approximately
11 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 15, 2025.
1"
NR
11"

9.8 8.9
BC=50/1"
BC=50/1"
BC=24
50/5"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-23

LABORATORY RESULTS
Lithologic Description
BORING LOG B-21
PAGE:

BORING LOG B-21
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67781°
Longitude: -117.66755°
Ground Surface Elevation (ft.): 784.5
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/15/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
780
775
770
765
760
755
750
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
PLOTTED: 02/14/2025 11:50 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1153
121.4
117.9
17 Asphalt: approximately 3"
Aggregate Base: approximately 5"
Artificial Fill
Clayey SAND (SC): fine to medium sand, low
plasticity, brown, moist
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
olive gray, fine to medium sand, moist, trace
clay, highly weathered, very weak (R1)
increase in fines, fine sand
excavates as clayey sand (SC), light gray, fine
sand, low plasticity
The boring was terminated at approximately

10.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 16, 2025.
12"
9"
3"

13.0 9.8

10.2 BC=17
50/6"
BC=24
50/3"
BC=50/3"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-24

LABORATORY RESULTS
Lithologic Description
BORING LOG B-22
PAGE:

BORING LOG B-22
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67793°
Longitude: -117.66812°
Ground Surface Elevation (ft.): 783.5
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/16/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
780
775
770
765
760
755
750
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 PLOTTED: 02/14/2025 11:50 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1154
123.3
Asphalt: approximately 3"
Aggregate Base: approximately 5"
Artificial Fill
Clayey SAND (SC): fine to medium sand,
brown, moist, trace fine subrounded gravel
Capistrano Formation
SANDSTONE: excavates as silty sad (SM),
light gray, fine to medium sand, moist, highly
weathered, very weak (R1)
trace clay
olive gray
The boring was terminated at approximately

10.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 16, 2025.
12"
16"
2"

11.7 12.6

10.6 7.3
BC=16
50/6"
BC=40
37 50/4"
BC=50/6"
31 Hand auger 5ft bgs
11 R-Value Test
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-25

LABORATORY RESULTS
Lithologic Description
BORING LOG B-23
PAGE:

BORING LOG B-23
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67842°
Longitude: -117.66787°
Ground Surface Elevation (ft.): 787.5
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/16/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
785
780
775
770
765
760
755
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
PLOTTED: 02/14/2025 11:50 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1155
116.8
17 Asphalt: approximately 3"
Aggregate Base: approximately 5"
Artificial Fill
Clayey SAND (SC): fine to medium sand,
dark brown, moist, trace fine gravel
Capistrano Formation
SANDSTONE: excavates silty sand (SM),
light gray, fine to medum sand, moist, highly
weathered, very weak (R1)
decrease in fines
increase in fines, fine sand
The boring was terminated at approximately
11 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 16, 2025.
18"
6"
14"

10.9 10.4

9.4 BC=13
30 40
BC=50/6"
BC=30
38 50/2"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-26

LABORATORY RESULTS
Lithologic Description
BORING LOG B-24
PAGE:

BORING LOG B-24
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67844°
Longitude: -117.66842°
Ground Surface Elevation (ft.): 785.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/16/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
780
775
770
765
760
755
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 PLOTTED: 02/14/2025 11:50 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1156
122.8
Asphalt: approximately 3"
Aggregate Base: approximately 6"
Artificial Fill
Clayey SAND (SC): fine to medium sand, low
plasticity, brown, moist, trace fine gravel
Capistrano Formation
SANDSTONE: excavates silty sand (SM),
light gray, fine to medium sand, moist, highly
weathered, very weak (R1)
trace coarse sand
decrease in fines
The boring was terminated at approximately
10 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 14, 2025.
6"
8"
1"

12.7 10.7

4.3 BC=50/6"
BC=25
50/2"
BC=50/1"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-27

LABORATORY RESULTS
Lithologic Description
BORING LOG B-25
PAGE:

BORING LOG B-25
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67723°
Longitude: -117.66720°
Ground Surface Elevation (ft.): 781.5
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/14/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
780
775
770
765
760
755
750
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 PLOTTED: 02/14/2025 11:50 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1157
118.9
25 Asphalt: approximately 3.5"
Aggregate Base: approximately 5"
Artificial Fill
Clayey SAND (SC): fine to medium sand, low
plasticity, light gray, moist
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
light gray, fine to medium sand, moist, higly
weatheres, very weak (R1)
decrease in fines
The boring was terminated at approximately

10.5 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 14, 2025.
4"
8"
6"

10.6 10.5

8.8 BC=50/4"
BC=27
50/2"
BC=50/6"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-28

LABORATORY RESULTS
Lithologic Description
BORING LOG B-26
PAGE:

BORING LOG B-26
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67695°
Longitude: -117.66739°
Ground Surface Elevation (ft.): 779.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/14/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
745
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 PLOTTED: 02/14/2025 11:50 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1158
124.4
117.8
114.9
Asphalt: approximately 4"
Aggregate Base: approximately 6"
Artificial Fill
Silty SAND with Gravel (SM): fine to medium
sand, brown, moist
Capistrano Formation
SANDSTONE: excavaes as silty sand (SM),
light gray, fine to medium sand, moist, highly
weathered, very weak (R1)
increase in fines
fine sand
decrease in fines
increase in fines
excavates as poorly graded sand with silt
(SP-SM)
excavates as poorly graded sand (SP), fine
sand
excavates as silty sand (SM)
The boring was terminated at approximately
26 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 14, 2025.
9"
12"
6"
12"
6"
6"
5"
11"

10.0 9.6

9.7 12.8

11.2 BC=25
50/3"
BC=23
50/6"
BC=50/6"
BC=14
50/6"
BC=50/6"
BC=50/6"
BC=50/5"
BC=31
50/5"
NP
Hand auger 5ft bgs
NP Corrosion Test
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-29

LABORATORY RESULTS
Lithologic Description
BORING LOG B-27
PAGE:

BORING LOG B-27
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67696°
Longitude: -117.66696°
Ground Surface Elevation (ft.): 779.5
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/14/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
745
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
5 6
7 8
9 PLOTTED: 02/14/2025 11:50 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1159
114.1
113.5
112.6
22 Asphalt: approximately 3.5"
Aggregate Base: approximately 4"
Artificial Fill
Clayey SAND with Gravel (SC): fine to
medium sand, brown, moist
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
yellow, fine to medium sand, moist, highly
weathered, very weak (R1)
decrease in fines
excavates as clayey sand (SC), gray, fine
sand, low to medium plasticity
excavates as silty sand (SM), light gray, fine to
medium sand, trace clay
fine to coarse sand, decrease in fines
fine to medium sand
decrease in fines
excavates as poorly graded sand with silt
(SP-SM), fine to medium sand
excavates as poorly graded sand (SP), fine to
coarse sand
The boring was terminated at approximately
25 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 14, 2025.
10"
5"
9"
6"
12"
6"
11"
2"

8.8 11.0

9.6 7.6

8.2 BC=34
50/4"
BC=50/5"
BC=34
50/3"
BC=50/6"
BC=27
50/6"
BC=50/6"
BC=25
50/5"
BC=50/2"
Hand auger 5ft bgs
Direct Shear Test
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-30

LABORATORY RESULTS
Lithologic Description
BORING LOG B-28
PAGE:

BORING LOG B-28
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67686°
Longitude: -117.66706°
Ground Surface Elevation (ft.): 778.5
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/14/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
745
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
3 4
5 6
7 8
PLOTTED: 02/14/2025 11:51 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1160
97 19
Asphalt: approximately 3"
Aggregate Base: approximately 6"
Artificial Fill
Silty Clayey SAND (SC-SM): fine to medium
sand, brown, moist
The boring was terminated at approximately 5
ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 16, 2025.

Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-31

LABORATORY RESULTS
Lithologic Description
BORING LOG INF-1
PAGE:

BORING LOG INF-1
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67731°
Longitude: -117.67016°
Ground Surface Elevation (ft.): 781.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/16/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
780
775
770
765
760
755
750
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 PLOTTED: 02/14/2025 11:51 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1161
100 20
Asphalt: approximately 5"
Aggregate Base: approximately 6"
Artificial Fill
Clayey SAND (SC): fine to medium sand, low
plasticity, brown, moist, trace angular gavel
light gray
Capistrano Formation
SANDSTONE: excavates as silty sand (SM),
gray, fine to medium sand, moist, trace clay,
highly weathered, very weak (R1)
The boring was terminated at approximately
10 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 16, 2025.
18"
11"
BC=8
14 12
BC=39
50/5"
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-32

LABORATORY RESULTS
Lithologic Description
BORING LOG INF-2
PAGE:

BORING LOG INF-2
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67685°
Longitude: -117.66987°
Ground Surface Elevation (ft.): 777.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/16/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
745
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
PLOTTED: 02/14/2025 11:51 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1162
99 15
Asphalt: approximately 5"
Aggregate Base: approximately 5"
Artificial Fill
Clayey SAND (SC): fine to medium sand,
brown, moist
olive
The boring was terminated at approximately 5
ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 16, 2025.

Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-33

LABORATORY RESULTS
Lithologic Description
BORING LOG INF-3
PAGE:

BORING LOG INF-3
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67648°
Longitude: -117.66952°
Ground Surface Elevation (ft.): 777.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/16/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
745
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 PLOTTED: 02/14/2025 11:51 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1163
100 7.5
Asphalt: approximatey 3"
Aggregate Base: approximately 6"
Artificial Fill
Clayey SAND (SC): fine to medium sand,
brown, moist, trace angular gravel
ollive gray
Capistrano Formation
SANDSTONE: excavates as well graded
sand with silt (SW-SM), olive gray, fine to
medium sand, moist highly weathered, very
weak (R1)
The boring was terminated at approximately
10 ft. below ground surface. The boring was
backfilled with auger cuttings and patched at
surface on January 16, 2025.
18"
18"
BC=7
10 12
BC=18
34 50
Hand auger 5ft bgs
Groundwater was not observed during drilling or after
completion.

GENERAL NOTES:

The exploration location and elevation are approximate.

Coordinates were obtained from Google Earth and the elevation was obtained from ALTA survey map prepared by PBLA
Surveying.

GROUNDWATER LEVEL INFORMATION:
1 of 1

FIELD EXPLORATION
A-34

LABORATORY RESULTS
Lithologic Description
BORING LOG INF-4
PAGE:

BORING LOG INF-4
FIGURE
Dry Unit Wt. (pcf)Passing #4 (%)Passing #200 (%)
Latitude: 33.67622°
Longitude: -117.66915°
Ground Surface Elevation (ft.): 777.0
Surface Condition: Asphalt
Not Available
Drilling Company: 2R Drilling
Drilling Method:

Drilling Equipment:

Sunny Bore Diameter:

Hammer Type - Drop: 140 lb. Auto - 30 in.

Logged By:

Date Begin - End:

Hor.-Vert. Datum:

Weather:

Drill Crew:

CME-75
8 in. O.D.

D. Edrees
Plunge: -90 degrees Hollow Stem Auger
Cody/ David/ Antonio
1/16/2025
Depth (feet)
5 10
15 20
25 30
Elevation (feet)
775
770
765
760
755
750
745
Graphical LogBlow Counts(BC)= Uncorr. blows/6 inRecovery(NR=No Recovery)USCSSymbolWaterContent (%)Liquid LimitsPlasticity Index(NP=NonPlastic)Additional Tests/Remarks Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
SampleNumber
1 2
PLOTTED: 02/14/2025 11:51 AM BY: HMarquez
gINT FILE: Klf_gint_master_2025 PROJECT NUMBER: 25003229.001A OFFICE FILTER: LAGUNA HILLSgINT TEMPLATE: E:KLF_STANDARD_GINT_LIBRARY_2025.GLB [__KLF_BORING/TEST PIT SOIL LOG] DATE:

CHECKED BY: H.M
DRAWN BY: D.E
PROJECT NO.:
25003229.001ASample Type
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1164
25003229.001A/LH25R178197R April 4, 2025
© 2025 Kleinfelder (Revised November 21, 2025)

APPENDIX B

LABORATORY TESTING
Item: 11
1165
25003229.001A/LH25R178197R Page B-1 April 4, 2025
© 2025 Kleinfelder (Revised November 21, 2025)

APPENDIX B

LABORATORY TESTING

GENERAL
Laboratory tests were performed on selected samples as an aid in classifying the soils and to evaluate physical properties of the soils that may affect foundation design and construction procedures. Laboratory testing was performed by both Kleinfelder and AP Engineering and Testing, Inc. of Pomona, California. The tests were performed in general conformance with the current ASTM or Caltrans standards. A description of the laboratory-testing program is presented below.

MOISTURE AND UNIT WEIGHT
Moisture content and dry unit weight testing was performed on a selected sample recovered from our borings. Moisture contents were determined in general accordance with ASTM Test Method D2216; dry unit weight was calculated using the entire weight of the samples collected in general accordance with ASTM Test Method D7263. Results of these tests are presented on the boring logs in Appendix A.

WASH SIEVE
Selected soil samples were tested for the percent passing the No. 200 sieve, which was performed by wash sieving in accordance with ASTM Standard Test Method D1140. Results of these tests are presented on the boring logs in Appendix A.

SIEVE AND HYDROMETER ANALYSIS
Sieve analysis of selected samples was performed to evaluate the grain size distribution of the onsite soils and to aid in classification of the soils. Sieve analysis and hydrometer analysis was performed in accordance with ASTM Standard Test Method D6913. The results of the tests are presented on the boring logs in Appendix A and as an attachment in this appendix.

DIRECT SHEAR
Direct shear testing was performed on a relatively undisturbed sample to evaluate the shear strength characteristics of the onsite soils. Direct shear testing was performed in general accordance with ASTM Standard Test Method D3080. The results of the testing are presented as an attachment in this appendix.

Item: 11
1166
25003229.001A/LH25R178197R Page B-2 April 4, 2025
© 2025 Kleinfelder (Revised November 21, 2025)

MODIFIED PROCTOR
Modified Proctor (maximum dry density and optimum moisture content) testing was performed on two select bulk samples of the near surface soils to evaluate the compaction characteristics of the onsite soils. The testing was performed in general accordance with ASTM Standard Test Method D1557. The test results are attached to this appendix.

R-VALUE
Resistance value (R-value) tests were performed on two select bulk soil samples to evaluate pavement support characteristics of the near-surface onsite soils. R-value tests were performed in accordance with ASTM Standard Test Method D2844. The test results are attached to this appendix.

SOIL CORROSIVITY TESTS
A series of chemical tests were performed on selected samples of the near-surface soils to estimate pH, resistivity and sulfate and chloride contents. The samples were tested for pH and minimum resistivity, soluble chlorides, and soluble sulfates, respectively. The tests were performed by AP Engineering and Testing, Inc. Test results may be used by a qualified corrosion engineer to evaluate the general corrosion potential with respect to construction materials. The results of the tests are presented in the body of the report and are attached to this appendix.

Item: 11
1167
SYMBOL
1 GRAVEL

3.5 0.0

1.2 SAMPLE
NO.

SAMPLE IDENTIFICATION
BORING
NO.

INF-1
INF-2
INF-3

4.5-5

8.5 4.5-5

PERCENTAGES
1 2
NM
DEPTH
(ft.) FINES

18.6 20.3

15.3 SAND

77.9 79.7

83.5 NM

SOIL CLASSIFICATION
Silty Sand (SM)
Silty Sand (SM)
Silty Sand (SM)
PI

ATTERBERG LIMITS
LL
NM NM
NM
NM
PL
NM
NM NM
INF-4 2 8.5 0.0 92.5 7.5 NM NM NM Well Graded Sand with Silt (SW) 0 10
20 30
40 50
60 70
80 90
100
100.000 10.000 1.000 0.100 0.010 0.001

CUMULATIVE PERCENT PASSING

GRAIN SIZE IN MILLIMETERS

SILT CLAY

COBBLE GRAVEL SAND SILT CLAY

GRAIN SIZE DISTRIBUTION
Proposed Costco Wholesale Warehouse and
Fuel Facility
26602 Towne Centre Drive
2/10/2025 Foothill Ranch, California
25003229.001A
M.Magaña
2/5/2025
M.Magaña
FIGURE
TESTED BY:

DATE:

CHECKED BY:

DATE:

PROJECT NO.:

KLEINFELDER - 620 Magnolia Avenue, Building G | Ontario, California 91762 | PH: (909) 657-1716 | FAX: (909) 988-0185 | www.kleinfelder.com Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Well Graded Sand with Silt (SW-SM) Silty Clayey Sand (SC-SM) Clayey Sand (SC) Silty Sand (SM) Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California Proposed Costco Wholesale Warehouse 26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1168
Testing performed in general accordance with ASTM D4318 1 1
5 5

7.5 Silty Sand (SM)
Silty Sand (SM)
SYMBOL
25 22 3

N/A N/A N/A
27 22 5
5 B-5 1
B-1 1
B-3 2
B-7
B-9

SOIL CLASSIFICATION

SAMPLE IDENTIFICATION
Silty Sand (SM)
Silty Sand (SM)
30 25 5
29 26 3

ATTERBERG LIMITS

LL PL PI BORING
NO.

SAMPLE
NO. DEPTH (ft)
5 Silty Sand (SM)
MH or OH
ML or OL
CH or OH
CL-ML
CL or OL
0 10
20 30
40 50
60 0 10 20 30 40 50 60 70 80 90 100 110

PLASTICITY INDEX (PI)

LIQUID LIMIT (LL)
PROJECT NO.:

TESTED BY:

DATE:

CHECKED BY:

DATE:

FIGURE
0 PROJECT NO.: 25003229.001A
TESTED BY: N.Brown
DATE: 2/5/2025
CHECKED BY: M.Magaña
DATE: 2/10/2025
Proposed Costco Wholesale Warehouse
and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California
PLASTICITY TESTING KLEINFELDER - 620 South Magnolia Ave, Bldg G | Ontario, CA | PH: (909) 657-1716 | FAX: (909) 988-0185 | www.kleinfelder.com Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive

NP NP NP
Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California Proposed Costco Wholesale Warehouse 26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1169
Testing performed in general accordance with ASTM D4318

SOIL CLASSIFICATION

SAMPLE IDENTIFICATION
Silty Sand (SM)
Silty Sand (SM)

N/A N/A N/A

N/A N/A N/A

ATTERBERG LIMITS

LL PL PI BORING
NO.

SAMPLE
NO. DEPTH (ft)
0-5 Silty Sand with Gravel (SM)
SYMBOL
30 22 8
31 20 11

N/A N/A N/A
0-5
B-20 1
B-12 1
B-15 1
B-23
B-27
0-5
5 5
Clayey Sand (SC)
Clayey Sand (SC)
1 1
MH or OH
ML or OL
CH or OH
CL-ML
CL or OL
0 10
20 30
40 50
60 0 10 20 30 40 50 60 70 80 90 100 110

PLASTICITY INDEX (PI)

LIQUID LIMIT (LL)
FIGURE
0 PROJECT NO.: 25003229.001A
TESTED BY: N.Brown
DATE: 2/10/2025
CHECKED BY: M.Magaña
DATE: 2/11/2025
Proposed Costco Wholesale Warehouse
and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California

PLASTICITY TESTING
KLEINFELDER - 620 South Magnolia Ave, Bldg G | Ontario, CA | PH: (909) 657-1716 | FAX: (909) 988-0185 | www.kleinfelder.com Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive

NPNPNP NPNPNP NPNPNP
Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California Proposed Costco Wholesale Warehouse 26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1170
Project Name: Costco Foothill Ranch, CA GEO Tested By: ST Date: 01/27/25 Project No.: 25003229.001A Computed By: JP Date: 02/03/25 Boring No.: B‐28 Checked by: AP Date: 02/03/25
Sample No.: 4 Depth (ft): 12.5
Sample Type: Mod. Cal.

Soil Description: Silty Sand
Test Condition: Inundated Shear Type: Regular
Wet
Unit Weight
(pcf)
Dry
Unit Weight
(pcf)
Initial
Moisture
Content (%)
Final
Moisture
Content (%)
Initial Degree
Saturation
(%)
Final Degree
Saturation
(%)
Normal
Stress
(ksf)
Peak
Shear
Stress (ksf)
Ultimate
Shear
Stress (ksf)
1 1.058 0.718
2 2.196 1.476
4 3.744 2.580
90 DIRECT SHEAR TEST RESULTS
ASTM D 3080
122.2 113.5 7.6 16.1 43
0 1
2 3
4 5
0 0.1 0.2 0.3
Shear Stress (ksf)
Shear Deformation (Inches)
1 ksf 2 ksf 4 ksf
0 1
2 3
4 5
6 0 1 2 3 4 5 6 7 8 9 10 11 12
Shear Stress (ksf)
Normal Stress (ksf)
Peak: C=200 psf; ɸ=42˚
Ultimate: C=100 psf; ɸ=32˚
Normal Stress:

Item: 11
1171
Boring No.: B-11
Sample No.: 1
Depth: 0-5
Material Description: Clayey Sand (SC)
Maximum Dry Unit Weight (pcf)
Optimum Water Content (%)
Oversize Fraction, retained on 3/8 (%)
Tested in accordance with: ASTM D1557, Method B
na
<5
Bulk Specific Gravity of Oversize Fraction na

7.6 Uncorrected Corrected
129.5 na
na = not applicable
Compaction Curve
Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive 2/10/2025
25003229.001A
D.Montemayor II
2/4/2025
M.Magaña
FIGURE
TESTED BY:

DATE:

CHECKED BY:

DATE:

PROJECT NO.:
100
110
120
130
140

0.0 5.0 10.0 15.0 20.0 25.0 30.0
Dry Unit Weight (pcf)
Water Content (%)

2.75 2.70

2.65 2.60
Compaction Curve
Compaction Curve, Corrected
KLEINFELDER - 620 South Magnolia Avenue, Building G | Ontario, California 91762 | PH: (909) 657-1716 | FAX: (909) 988-0185 | www.kleinfelder.com Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California Proposed Costco Wholesale Warehouse 26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1172
Boring No.: B-16
Sample No.: 1
Depth: 0-5
Material Description: Clayey Sand (SC)
Maximum Dry Unit Weight (pcf)
Optimum Water Content (%)
Oversize Fraction, retained on 3/8 (%)
Tested in accordance with: ASTM D1557, Method B
na
<5
Bulk Specific Gravity of Oversize Fraction na

8.9 Uncorrected Corrected
128 na
na = not applicable
Compaction Curve
Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive 2/10/2025
25003229.001A
D.Montemayor II
2/4/2025
M.Magaña
FIGURE
TESTED BY:

DATE:

CHECKED BY:

DATE:

PROJECT NO.:
100
110
120
130
140

0.0 5.0 10.0 15.0 20.0 25.0 30.0
Dry Unit Weight (pcf)
Water Content (%)

2.75 2.70

2.65 2.60
Compaction Curve
Compaction Curve, Corrected
KLEINFELDER - 620 South Magnolia Avenue, Building G | Ontario, California 91762 | PH: (909) 657-1716 | FAX: (909) 988-0185 | www.kleinfelder.com Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California Proposed Costco Wholesale Warehouse 26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1173
Boring No.:

Sample No.:

Depth:

Material Description:

Test Procedure: ASTM D2844
Specimen No. B
Moisture at Test (%)
Dry Unit Weight at Test (pcf)
Expansion Pressure (psf)
19 15

21.6 568.4
A

10.2 123.6

0.0 792.0
B-20
Exudation Pressure (psi)
Resistance Value
R - VALUE AT 300 PSI EXUDATION PRESSURE
1 10.6
Clayey Sand (SC)
C
119.3

11.5 123.0
0-5

26.0 212.4
1430
0 10
20 30
40 50
60 70
80 90
100
050100150200250300350400450500550600650700750800
R-Value
Exudation Pressure (psi)

R-VALUE
Proposed Costco Wholesale Warehouse and Fuel
Facility
26602 Towne Centre Drive
Foothill Ranch, California 2/11/2025
25003229.001A
M.Magaña
2/5/2025
M.Magaña
FIGURE
TESTED BY:

DATE:

CHECKED BY:

DATE:

PROJECT NO.:

KLEINFELDER - 620 Magnolia Avenue, Building G | Ontario, California 91762 | PH: (909) 657-1716 | FAX: (909) 988-0185 | www.kleinfelder.com Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California Proposed Costco Wholesale Warehouse 26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1174
Boring No.:

Sample No.:

Depth:

Material Description:

Test Procedure: ASTM D2844
Specimen No. B
Moisture at Test (%)
Dry Unit Weight at Test (pcf)
Expansion Pressure (psf)
18 16

21.6 543.2
A

11.6 118.3

0.0 260.0
B-23
Exudation Pressure (psi)
Resistance Value
R - VALUE AT 300 PSI EXUDATION PRESSURE
1 11.1
Clayey Sand (SC)
C
119.1

10.6 119.6
0-5

26.0 641.2
2016
0 10
20 30
40 50
60 70
80 90
100
050100150200250300350400450500550600650700750800
R-Value
Exudation Pressure (psi)

R-VALUE
Proposed Costco Wholesale Warehouse and Fuel
Facility
26602 Towne Centre Drive
Foothill Ranch, California 2/11/2025
25003229.001A
M.Magaña
2/5/2025
M.Magaña
FIGURE
TESTED BY:

DATE:

CHECKED BY:

DATE:

PROJECT NO.:

KLEINFELDER - 620 Magnolia Avenue, Building G | Ontario, California 91762 | PH: (909) 657-1716 | FAX: (909) 988-0185 | www.kleinfelder.com Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Proposed Costco Wholesale
Warehouse and Fuel Facility
26602 Towne Centre Drive
Foothill Ranch, California Proposed Costco Wholesale Warehouse 26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1175

CORROSION TEST RESULTS
Client Name: Kleinfelder AP Job No.: 25-1060
Project Name: Costco Foothill Ranch, CA GEO Date: 01/28/25 Project No.: 25003229.001A
Boring Sample Depth Soil pH Sulfate Content Chloride Content No. No. (feet) Description (ppm) (ppm)
B-2 1 0-5 Sandy Clay 8.0 37 6
B-11 1 0-5 Sandy Clay 8.0 8 4
B-16 1 0-5 Clayey Sand 8.4 119 12
B-27 1 0-5 Clayey Sand 8.7 101 9

NOTES: Resistivity Test and pH: California Test Method 643 Sulfate Content : California Test Method 417
Chloride Content : California Test Method 422
ND = Not Detectable
NA = Not Sufficient Sample
NR = Not Requested
Minimum
(ohm-cm)
2,767
Resistivity
3,147
1,907
2,048
Item: 11
1176
25003229.001A/LH25R178197R April 4, 2025
© 2025 Kleinfelder (Revised November 21, 2025)

APPENDIX C

INFILTRATION TEST RESULTS
Item: 11
1177
Project: Proposed Costco Wholesale Warehouse and Fuel Facility Tester DE
Date:

Location: INF-1
Time
Between
Readings
(minutes)
Total
Elapsed
Time
(minutes)
Initial
Depth
(feet, bgs)
Final
Depth
(feet, bgs)
Drop in Head
(feet)
Percolation
Rate
(min/in)
Tested
Infiltration Rate
(in/hour)
30 30 3.05 3.25 0.20 12.5 0.4
30 60 3.05 3.20 0.15 16.7 0.3
30 90 3.10 3.25 0.15 16.7 0.3
30 120 3.10 3.25 0.15 16.7 0.3
30 150 3.05 3.15 0.10 25.0 0.2
30 180 3.10 3.25 0.15 16.7 0.3
30 210 3.10 3.25 0.15 16.7 0.3
30 240 3.10 3.20 0.10 25.0 0.2
30 270 3.05 3.20 0.15 16.7 0.3
30 300 3.10 3.25 0.15 16.7 0.3
30 330 3.05 3.20 0.15 16.7 0.3
30 360 3.10 3.25 0.15 16.7 0.3

2.0 5.0

1.8 2
8 Boring Percolation Test Method Figure
25003229.001A
Proposed Costco Wholesale Warehouse and Fuel Facility
Method: Borehole Percolation Test Procedure January 17, 2025

INCREMENTAL INFILTRATION RATE
Presoak Level (ft, bgs):

Well bottom depth (ft, bgs)
Final period drop delta d (in):

Diameter of well casing (in)
Diameter of boring (in):
26602 Towne Centre Drive
Foothill Ranch, California
Project No.:

0.0 0.2

0.4 0.6

0.8 1.0
0 30 60 90 120 150 180 210 240 270 300 330 360
Infiltration Rate (in/hr)
Time (min)
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1178
Project: Proposed Costco Wholesale Warehouse and Fuel Facility Tester DE
Date:

Location: INF-2
Time
Between
Readings
(minutes)
Total
Elapsed
Time
(minutes)
Initial
Depth
(feet, bgs)
Final
Depth
(feet, bgs)
Drop in Head
(feet)
Percolation
Rate
(min/in)
Tested
Infiltration Rate
(in/hour)
30 30 8.05 8.10 0.05 50.0 0.1
30 60 8.05 8.10 0.05 50.0 0.1
30 90 8.05 8.10 0.05 50.0 0.1
30 120 8.05 8.10 0.05 50.0 0.1
30 150 8.05 8.10 0.05 50.0 0.1
30 180 8.05 8.10 0.05 50.0 0.1
30 210 8.05 8.10 0.05 50.0 0.1
30 240 8.05 8.10 0.05 50.0 0.1
30 270 8.05 8.10 0.05 50.0 0.1
30 300 8.05 8.10 0.05 50.0 0.1
30 330 8.05 8.10 0.05 50.0 0.1
30 360 8.05 8.10 0.05 50.0 0.1

5.0 10.0

0.6 2
8 Boring Percolation Test Method Figure
25003229.001A
Foothill Ranch, California
Method: Borehole Percolation Test Procedure January 17, 2025

INCREMENTAL INFILTRATION RATE
Presoak Level (ft, bgs):

Well bottom depth (ft, bgs)
Project No.:

Final period drop delta d (in):

Diameter of well casing (in)
Diameter of boring (in):

Proposed Costco Wholesale Warehouse and Fuel Facility
26602 Towne Centre Drive

0.0 0.2

0.4 0.6

0.8 1.0
0 30 60 90 120 150 180 210 240 270 300 330 360
Infiltration Rate (in/hr)
Time (min)
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
Item: 11
1179
Project: Proposed Costco Wholesale Warehouse and Fuel Facility Tester DE
Date:

Location: INF-3
Time
Between
Readings
(minutes)
Total
Elapsed
Time
(minutes)
Initial
Depth
(feet, bgs)
Final
Depth
(feet, bgs)
Drop in Head
(feet)
Percolation
Rate
(min/in)
Tested
Infiltration Rate
(in/hour)
30 30 3.05 3.10 0.05 50.0 0.1
30 60 3.05 3.10 0.05 50.0 0.1
30 90 3.05 3.10 0.05 50.0 0.1
30 120 3.05 3.10 0.05 50.0 0.1
30 150 3.05 3.07 0.02 125.0 0.04
30 180 3.05 3.10 0.05 50.0 0.1
30 210 3.05 3.07 0.02 125.0 0.04
30 240 3.05 3.07 0.02 125.0 0.04
30 270 3.05 3.10 0.05 50.0 0.1
30 300 3.05 3.10 0.05 50.0 0.1
30 330 3.05 3.10 0.05 50.0 0.1
30 360 3.05 3.10 0.05 50.0 0.1

2.0 5.1

0.6 2
8 Boring Percolation Test Method Figure
25003229.001A
Foothill Ranch, California
Method: Borehole Percolation Test Procedure January 17, 2025

INCREMENTAL INFILTRATION RATE
Presoak Level (ft, bgs):

Well bottom depth (ft, bgs)
Project No.:

Final period drop delta d (in):

Diameter of well casing (in)
Diameter of boring (in):

Proposed Costco Wholesale Warehouse and Fuel Facility
26602 Towne Centre Drive