Agenda packet — Yorba Linda City Council, February 3, 2026 (part 4 of 11)

19081 Yorba Linda Boulevard Residential Project
City of Yorba Linda Environmental Consistency Analysis
88 current staffing or equipment deficiencies in the service area. Therefore, impacts related to police protection services from the proposed Project would be less than significant. Therefore, no new impact related to police protection services would occur.
iii. School Services
No New Impact.

The Project site is located within the Placentia-Yorba Linda Unified School District (PYLUSD). PYLUSD operates a District Education Center, Education Service Center, 1 Adult Transition Program, 1 TK-12 online school, and 32 school sites including 20 elementary schools, 5 middle schools, 1 TK-8 school, 5 comprehensive high schools, 1 special education school, and 1 TK-12 home school (City of Yorba Linda, 2022). The HEIP PEIR describes that there is adequate capacity at all school levels within PYLUSD, including a remaining capacity of 3,753 elementary students, 906 middle school students, and 406 high school students (City of Yorba Linda, 2022).

The proposed Project includes the development of 62 residential units. Table PS-1 shows the estimated students that would be generated from the Project using the student generation rates for the PYLUSD listed in the HEIP PEIR.

Table PS-2: Estimated Number of Students Generated by the Project School Level Multi-Family Rate1 Number of Proposed
Units
Students Potentially
Generated by Project
Elementary School (K-5) 0.2216
62 14
Intermediate School (6-8) 0.1023 6
High School (9-12) 0.1384 9
Total 29
1 Source: City of Yorba Linda, 2022 (Table 4.7-4)
As shown in Table PS-1, the proposed 62 units could result in approximately 29 new students that would range in age from elementary through high school. Pursuant to Government Code Section 65995 et seq., the need for additional school facilities is addressed through compliance with school impact fee assessment. SB 50 (Chapter 407 of Statutes of 1998) sets forth a State school facilities construction program that includes restrictions on a local jurisdiction’s ability to condition a project on mitigation of a project’s impacts on school facilities in excess of fees set forth in the Government Code. These fees are collected by school districts at the time of issuance of building permits for development projects. Pursuant to Government Code Section 65995, applicants shall pay developer fees to the appropriate school districts at the time building permits are issued; and payment of the adopted fees provides full and complete mitigation of school impacts. Therefore, impacts related to school facilities would be less than significant with the Government Code required fee payments. Therefore, no new impact related to school services would occur.
iv. Parks
No New Impact.

The Project would develop 62 new residential units and 9,900 SF of common open space recreation area on the site for use by residents. The City has adopted a standard of 3 acres of parkland per 1,000 residents (not including joint-use or regional parks). As described in the HEIP PEIR, the City is currently in a deficit of approximately 32.2 acres of parkland. However, all residential developments within the City would be required to pay impact fees to offset the cost to expand or construct new park and recreational space and facilities to adequately serve the City’s growing population, pursuant to YLMC

Page 647 of 2028 ends

19081 Yorba Linda Boulevard Residential Project
City of Yorba Linda Environmental Consistency Analysis
89 Section 15.56. Therefore, impacts related to the need to provide new or altered park and recreation facilities in order to maintain acceptable service ratios would be less than significant with the payment of parkland fees. Therefore, the Project would result in no new or increased impacts related to parks. v. Other Public Facilities
No New Impact.

The Yorba Linda Public Library (YLPL) is located at 4852 Lakeview Drive, approximately 0.6 miles west of the Project site. The proposed Project includes the development of 62 residential units, which would result in an increase in demand for library services. As described previously, the Project is anticipated to result in up to 181 new residents. Due to the increase in residents on-site, the Project could incrementally increase the demand for library services at the YLPL. However, as identified in the HEIP PEIR, demand on library services as a result of HEIP buildout would be incremental and would not require the need for new or expanded physical library facilities. Therefore, impacts related to libraries from the proposed Project would be less than significant. Therefore, no new or more severe impact related to libraries would occur.

Conclusion
Based on the foregoing information, none of the conditions identified in State CEQA Guidelines Section 15162 that would trigger the need to prepare a subsequent or supplemental EIR or other environmental document to evaluate project impacts or mitigation measures exist regarding public services. There have not been (1) changes related to development of the Project site that involve new significant environmental effects or a substantial increase in the severity of previously identified effects; (2) substantial changes with respect to the circumstances under which development of the Project site is undertaken that require major revisions of the HEIP PEIR due to the involvement of new significant environmental effects or a substantial increase in the severity of previously identified effects; or (3) the availability of new information of substantial importance relating to significant effects or mitigation measures or alternatives that were not known and could not have been known when the HEIP PEIR was adopted as completed.

Because none of the conditions identified in State CEQA Guidelines Section 15162 would trigger the need to prepare a subsequent or supplemental EIR or other environmental document to evaluate project impacts, the Project is consistent with the HEIP PEIR.

HEIP PEIR Mitigation Measures
No mitigation measures related to public services are included in the HEIP PEIR. Project impacts would be less than significant; therefore, no mitigation measures related to public services are required.

Page 648 of 2028 ends

19081 Yorba Linda Boulevard Residential Project
City of Yorba Linda Environmental Consistency Analysis
90 5.8. RECREATION
Would the project: Substantial
Change in
Project or
Circumstances
Resulting in
New
Significant
Effects
New
Information
Showing
Greater
Significant
Effects than
Previous EIR
New
Information
Identifying
New
Mitigation
or
Alternative
to Reduce
Significant
Effect is
Declined
Minor
Technical
Changes
or
Additions
No New
Impact/
No
Impact
a) Would the project increase the use of
existing neighborhood and regional parks or
other recreational facilities such that substantial
physical deterioration of the facility would
occur or be accelerated?
b) Does the project include recreational
facilities or require the construction or
expansion of recreational facilities which might
have an adverse physical effect on the
environment?
Summary of Impacts Identified in the HEIP PEIR
The HEIP PEIR discussed impacts related to recreation under Section 4.8. The City currently has 27 developed and planned local public parks, totaling 186.08 acres. Additionally, there are three regional parks within the City and one regional park (Chino Hills State Park), which is accessible from the City. In total, these four regional parks consist of approximately 14,770 acres. The City also currently has joint-use agreements within 9 schools within PYLUSD for a total of 61.6 acres of joint-use park and recreation facilities. The City has an established park ratio requirement of 3 acres of local city parkland (not including joint-use or regional parks) per 1,000 residents. Based on the total acres of all parks and facilities within the City limits, a total of 171.08 acres of parkland (excluding joint-use facilities and regional parks) is being provided for a current park ratio of 2.52 acres of parkland per 1,000 residents. Therefore, the City has a current deficit of approximately 32.2 acres of parkland.

Using the City’s goal of 3 acres of local city parkland per 1,000 residents, the net increase in demand for parkland due to the buildout of the Project (7,085 new residents) would be approximately 21.26 acres.

Although the City does not meet its current park ratio requirement, there are approximately 14,770 acres of regional parks and 61.6 acres of joint-use parks that would serve future project residents Impacts Associated with the Proposed Project. Additionally, all future residential development would be required to provide adequate parkland or pay in-lieu fees pursuant to YLMC Section 15.56. Therefore, the HEIP PEIR determined impacts to parks and recreational facilities would be less than significant.

Page 649 of 2028 ends

19081 Yorba Linda Boulevard Residential Project
City of Yorba Linda Environmental Consistency Analysis
91 a) Increase the use of existing neighborhood and regional parks or other recreational facilities such that physical deterioration of the facility would be accelerated? No New Impact.

As described previously, it is estimated that the Project would result in the addition of 182 residents. Based on the City’s park dedication requirement of 3 acres per 1,000 persons, the Project would be required to provide 0.5 acres of parkland (approximately 21,780 SF). The Project proposed 9,900 SF of common open space including an open lawn with a shade structure, BBQ, and tables for resident use. Thus, the Project’s proposed on-site amenities would in part satisfy the City’s parkland requirement. The Project Applicant would also be subject to the payment of Parkland Dedication Fees per YLMC Section 15.56.

According to the HEIP PEIR, the City has approximately 186.08 acres of developed and planned parks and approximately 14,770 acres of regional parkland available for use by residents. Therefore, there are many recreational facilities in the area that can be used by the residents of the Project. Consistent with the findings of the HEIP PEIR, while the Project would increase the number of residents in the area, thereby increasing the need for and use of recreational facilities, the residents resulting from the Project would not increase the use of existing parks and recreational facilities such that physical deterioration of the facility would be accelerated. Through Project adherence to YLMC requirements and payment of Park Development Fees, the Project would not increase the use of existing neighborhood and regional parks or other recreational facilities such that substantial physical deterioration of the facility would occur or be accelerated. Therefore, impacts would be less than significant and no new or more severe impact would occur. b) Require the construction or expansion of recreational facilities which might have an adverse physical effect on the environment?
No New Impact.

The Project Applicant would be required to provide adequate parkland equal to 3 acres per 1,000 residents (0.5 acres) or pay an in-lieu fee prior per the City’s Park Dedications Fees Ordinance. As described above, the Project includes 9,900 SF of common open space. The impacts related to development of the open space recreation area are considered part of the impacts of the proposed Project as a whole and are analyzed throughout the various sections of this document. For example, activities such as excavation, grading, and construction as required for the recreation area are analyzed in the Air Quality (Section 5.1), Greenhouse Gas Emissions (Section 5.4), Noise (Section 5.6), and Transportation (Section 5.9) sections. The Project would also contribute park development fees pursuant to YLMC Section 15.56, to be used towards the future expansion or maintenance parks and recreational facilities, these fees are standard with every residential development, and the proposed Project would not require the construction or expansion of other recreational facilities that might have an adverse physical effect on the environment. As a result, impacts would be less than significant. Therefore, the Project would have no new or increased impacts related to expansion of recreational facilities.

Conclusion
Based on the foregoing information, none of the conditions identified in State CEQA Guidelines Section 15162 that would trigger the need to prepare a subsequent or supplemental EIR or other environmental document to evaluate project impacts or mitigation measures exist regarding recreation. There have not been (1) changes related to development of the Project site that involve new significant environmental effects or a substantial increase in the severity of previously identified effects; (2) substantial changes with respect to the circumstances under which development of the Project site is undertaken that require major revisions of the HEIP PEIR due to the involvement of new significant environmental effects or a substantial increase in the severity of previously identified effects; or (3) the availability of new information of substantial

Page 650 of 2028 ends

19081 Yorba Linda Boulevard Residential Project
City of Yorba Linda Environmental Consistency Analysis
92 importance relating to significant effects or mitigation measures or alternatives that were not known and could not have been known when the HEIP PEIR was adopted as completed.

HEIP PEIR Mitigation Measures
No mitigation measures related to recreation are included in the HEIP PEIR. Project impacts would be less than significant; therefore, no mitigation measures related to recreation are required.

Page 651 of 2028 ends

19081 Yorba Linda Boulevard Residential Project
City of Yorba Linda Environmental Consistency Analysis
93 5.9. TRANSPORTATION
Would the project: Substantial
Change in
Project or
Circumstances
Resulting in
New
Significant
Effects
New
Information
Showing
Greater
Significant
Effects than
Previous EIR
New
Information
Identifying
New
Mitigation
or
Alternative
to Reduce
Significant
Effect is
Declined
Minor
Technical
Changes
or
Additions
No New
Impact/
No
Impact
a) Conflict with a program, plan, ordinance or
policy addressing the circulation system,
including transit, roadway, bicycle and
pedestrian facilities?
b) Would the project conflict or be inconsistent
with CEQA Guidelines section 15064.3,
subdivision (b)?
c) Substantially increase hazards due to a design
feature (e.g., sharp curves or dangerous
intersections) or incompatible uses (e.g., farm
equipment)?
d) Result in inadequate emergency access?
Summary of Impacts Identified in the HEIP PEIR
The HEIP PEIR discussed impacts related to transportation under Section 4.9. The HEIP PEIR describes that the project would not conflict with applicable General Plan goals and policies or with SCAG’s Connect SoCal.

Thus, the project would not conflict with a program, plan, ordinance or policy addressing the circulation system, including transit, roadway, bicycle and pedestrian facilities, and impacts would be less than significant.

The City of Yorba Linda has identified a vehicle miles traveled (VMT) per service population (SP) significance threshold of 35.1. The HEIP PEIR’s VMT analysis determined base year (2016) VMT per SP would be 33.29 while the cumulative year (2045) VMT per SP would be 33.74. Thus, the project would not exceed the City’s VMT impact threshold for baseline and cumulative conditions by 5.16 percent and 3.87 percent, respectively.

Therefore, the project would not conflict or be inconsistent with CEQA Guidelines section 15064.3, subdivision (b), and impacts would be less than significant.

All future roadway system improvements associated with development and redevelopment activities under the project would be designed in accordance with the City’s roadway design standards and improvements would be subject to review by the City of Yorba Linda, Public Works Department of. Therefore, the HEIP PEIR determined implementation of the project would not result in hazardous conditions, create conflicting uses, or cause a detriment to emergency vehicles access. Impacts would be less than significant.

Page 652 of 2028 ends

19081 Yorba Linda Boulevard Residential Project
City of Yorba Linda Environmental Consistency Analysis
94 Impacts Associated with the Proposed Project
The following report was used to prepare this section:
• Vehicle Miles Traveled (VMT) Screening Analysis. Prepared by EPD Solutions, Inc, on May 28, 2025. (Appendix I).
a) Conflict with a program, plan, ordinance, or policy addressing the circulation system, including transit, roadway, bicycle, and pedestrian facilities?
No New Impact.

The proposed Project involves the development of 62 residential units. Construction and operation of the Project would introduce new vehicular traffic from workers and proposed operations. Vehicular access to the proposed Project would be provided via one driveway on Yorba Linda Boulevard. Vehicular traffic to and from the Project site would utilize the existing network of regional and local roadways that currently serve the Project area. The Project would construct internal roadways that would provide connection to and from proposed residences to adjacent residential areas. However, final design plans would be subject to review and approval by the City prior to the issuance of building permits. Additionally, as presented in Section 5.5, Land Use and Planning, implementation of the Project would not result in an inconsistency with the adopted Connect SoCal. Overall, because the Project is within the total unit count of the HEIP PEIR, the traffic that would be generated from operation of the Project is within the assumptions of the HEIP PEIR. As such, consistent with the findings of the HEIP PEIR, the Project would not interfere with adopted plans, programs, ordinances, or policies regarding roadway facilities; therefore, impacts would be less than significant.

Alternative Transportation
Sidewalks currently exist along Project frontage on Yorba Linda Boulevard. The existing sidewalk fronting the Project site would be removed and replace as part of Project construction. However, once Project construction is complete, the sidewalk would be available to the public for regular use. Additionally, according to Figure CR-4 of the City's General Plan Circulation Element, there are no existing or planned bicycle lanes along Project frontage on Yorba Linda Boulevard (City of Yorba Linda, 2016c). Thus, the proposed Project would not conflict with sidewalks or bike lanes along Yorba Linda Boulevard.

The closest bus route to the site is Orange County Transportation Authority (OCTA) Route 26 which serves Fullerton to Yorba Linda via Commonwealth Avenue and Yorba Linda Avenue. The closest bus stop along Route 26 is located 0.7 miles to the west of the Project site on Yorba Linda Boulevard. Buildout of the Project site would not disrupt the existing bus route. Therefore, the Project would not conflict with alternative transportation and Project impacts to transit, bicycle, and pedestrian facilities would be less than significant.

As such, there would be no new or increased impacts.
b) Conflict or be inconsistent with CEQA Guidelines § 15064.3, subdivision (b)? No New Impact.

Senate Bill (SB) 743 was signed by Governor Brown in 2013 and required the Governor’s Office of Planning and Research (OPR) to amend the State CEQA Guidelines to provide an alternative to LOS for evaluating transportation impacts. SB743 specified that the new criteria should promote the reduction of GHGs, the development of multimodal transportation networks and a diversity of land uses. In response, Section 15064.3 was added to the CEQA Guidelines beginning January 1, 2019, with the provisions of the section applying statewide beginning on July 1, 2020. State CEQA Guidelines Section 15064.3, Determining the Significance of Transportation Impacts, states that VMT is the most appropriate measure of transportation impacts and provides lead agencies with the discretion to choose the most appropriate methodology and thresholds for evaluating VMT.

Page 653 of 2028 ends

19081 Yorba Linda Boulevard Residential Project
City of Yorba Linda Environmental Consistency Analysis
95 The City’s Traffic Impact Analysis Guidelines (2020) provides VMT screening thresholds to identify projects that would be considered to have a less-than significant impact on VMT and therefore could be screened from further analysis. According to the City’s Guidelines, residential and office projects located within a low VMT-generating area may be presumed to have a less than significant impact. The VMT Screening Analysis prepared for the proposed Project (Appendix I) used the NOCC+ (North Orange County Collaborative) VMT Traffic Study Screening Tool which determined that the Project site is located within TAZ 175 which is considered a Low-VMT area. Additionally, the Project is consistent with the site’s underlying land use and zoning designations. Therefore, the Project meets the Low VMT Area Screening Criteria and can be presumed to have a less than significant impact related to VMT. This is consistent with the findings of the HEIP PEIR which determined VMT impacts from HEIP buildout would be less than significant. Therefore, no new or more severe impact would occur from implementation of the Project.
c) Substantially increase hazards due to a geometric design feature (e.g., sharp curves or dangerous intersections) or incompatible uses (e.g., farm equipment)? No New Impact.

Vehicular access to the Project site would be provided via one driveway on Yorba Linda Boulevard. Vehicular traffic to and from the Project site would utilize the existing network of regional and local roadways that currently serve the Project area. The Project would not introduce any new roadways or introduce a land use that would conflict with existing urban land uses in the surrounding area. Internal circulation would be provided via 24-foot-wide drive-aisles that double as a fire access lanes. Design of the proposed Project, including the internal private roadway, ingress, egress, and other streetscape changes are subject to the City’s development standards. For example, the design of the Project streets would be reviewed to ensure fire engine accessibility and turn around area is provided to the fire code standards. As a result, impacts related to vehicular circulation design features would be less than significant, and no new or increased impacts would occur.
d) Result in inadequate emergency access?
No New Impact.

The proposed construction activities, including equipment and supply staging and storage, would occur within the Project site, and would not restrict access of emergency vehicles to the Project site or adjacent areas. The installation of Project driveways, connections to existing infrastructure systems, and construction of new infrastructure that would be implemented during construction of the proposed Project could require the temporary closure of one side or portions of Yorba Linda Boulevard for a short period of time (e.g., hours or a few days). However, the construction activities would be required to ensure emergency access in accordance with Section 503 of the CFC (Title 24, California Code of Regulations, Part 9), which would be ensured through the City’s permitting process. Thus, implementation of the Project through the City’s permitting process would ensure existing regulations are adhered to and would reduce potential construction related emergency access impacts to a less-than-significant level. No new impact would occur.

Conclusion
Based on the foregoing information, none of the conditions identified in State CEQA Guidelines Section 15162 that would trigger the need to prepare a subsequent or supplemental EIR or other environmental document to evaluate project impacts or mitigation measures exist regarding transportation. There have not been (1) changes related to development of the Project site that involve new significant environmental effects or a substantial increase in the severity of previously identified effects; (2) substantial changes with respect to the circumstances under which development of the Project site is undertaken that require major revisions of the HEIP PEIR due to the involvement of new significant environmental effects or a substantial increase in the severity of previously identified effects; or (3) the availability of new information of substantial

Page 654 of 2028 ends

19081 Yorba Linda Boulevard Residential Project
City of Yorba Linda Environmental Consistency Analysis
96 importance relating to significant effects or mitigation measures or alternatives that were not known and could not have been known when the HEIP PEIR was adopted as completed.

HEIP PEIR Mitigation Measures
No mitigation measures related to transportation are included in the HEIP PEIR. Project impacts would be less than significant; therefore, no mitigation measures related to recreation are required.

Page 655 of 2028 ends

19081 Yorba Linda Boulevard Residential Project
City of Yorba Linda Environmental Consistency Analysis
97 5.10. TRIBAL CULTURAL RESOURCES
a) Would the project cause a substantial
adverse change in the significance of a
tribal cultural resource, defined in Public
Resources Code section 21074 as either a
site, feature, place, cultural landscape that
is geographically defined in terms of the
size and scope of the landscape, sacred
place, or object with cultural value to a
California Native American tribe, and that
is:

Summary of Impacts Identified in the HEIP PEIR
The HEIP PEIR discussed impacts related to tribal cultural resources under Section 4.10. The HEIP PEIR determined implementation of the project has the potential cause a substantial adverse change in the significance of tribal cultural resources that may be buried beneath the housing opportunity sites’ surface or in on-site vegetation. However, implementation of MM 4.10-1 would ensure that grading and other grounddisturbing activities during construction are monitored by a qualified archaeologist as well as tribal monitors.

The mitigation measure further requires the proper treatment of any resources that may be uncovered, and the avoidance of disturbance in areas where potential resources are uncovered. With implementation of the required mitigation measure, the project would not cause a substantial adverse change in the significance of a tribal cultural resource and potential impacts would be reduced to less than significant levels.

Impacts Associated with the Proposed Project
a) Would the project cause a substantial adverse change in the significance of a tribal cultural resource, defined in Public Resources Code Section 21074 as either a site, feature, place, cultural landscape that is geographically defined in terms of the size and scope of the landscape, sacred place, or object with cultural value to a California Native American tribe, and that is:

Page 656 of 2028 ends

19081 Yorba Linda Boulevard Residential Project
City of Yorba Linda Environmental Consistency Analysis
98 i. Listed or eligible for listing in the California Register of Historical Resources, or in a local register of historical resources as defined in Public Resources Code section 5020.1(k)? ii. A resource determined by the lead agency, in its discretion and supported by substantial evidence, to be significant pursuant to criteria set forth in subdivision (c) of Public Resources Code Section 5024.1. In applying the criteria set forth in subdivision (c) of Public Resource Code Section 5024.1, the lead agency shall consider the significance of the resource to a California Native American tribe?
No New Impact.

The Project site is completely disturbed and developed with a single-family residences consisting of three buildings, various ancillary structures such as garages, storage sheds and share structures, as well as a small orchard with additional ornamental landscaping including trees and shrubs. Due to the disturbed nature of the site, it is unlikely that implementation of the proposed Project would impact tribal cultural resources.

However, if previously undocumented tribal cultural resources are identified during ground disturbing activities, a qualified monitor shall be contacted to assess the nature and significance of the find and divert earthmoving activities, if necessary, in accordance with MM 4.10-1. Compliance with MM 4.10-1 would reduce potential impacts related to tribal cultural resources to a less-than-significant level. Therefore, the proposed Project would be consistent with the analysis in the HEIP PEIR and no new impact would occur.

Conclusion
Based on the foregoing information, none of the conditions identified in State CEQA Guidelines Section 15162 that would trigger the need to prepare a subsequent or supplemental EIR or other environmental document to evaluate project impacts or mitigation measures exist regarding tribal cultural resources. There have not been (1) changes related to development of the Project site that involve new significant environmental effects or a substantial increase in the severity of previously identified effects; (2) substantial changes with respect to the circumstances under which development of the Project site is undertaken that require major revisions of the HEIP PEIR due to the involvement of new significant environmental effects or a substantial increase in the severity of previously identified effects; or (3) the availability of new information of substantial importance relating to significant effects or mitigation measures or alternatives that were not known and could not have been known when the HEIP PEIR was adopted as completed.

HEIP PEIR Mitigation Measures
MM 4.10-1 Prior to the commencement of any ground disturbing activity at the Project sites, the Project Applicant shall retain a Native American Monitor approved by the NAHC. A copy of the executed contract shall be submitted to the City of Yorba Linda Planning Department prior to the issuance of any permit necessary to commence a grounddisturbing activity. The Tribal monitor will only be present on-site during the construction phases that involve grounddisturbing activities into areas of undisturbed soils. The Tribal Monitor will complete daily monitoring logs that will provide descriptions of the day’s activities, including construction activities, locations, soil, and any cultural materials identified. The on-site monitoring shall end when all grounddisturbing activities on the Project Site are completed, or when the Tribal Representatives and Tribal Monitor have indicated that all upcoming grounddisturbing activities at the Project Site have little to no potential for impacting Tribal Cultural Resources.

Page 657 of 2028 ends

19081 Yorba Linda Boulevard Residential Project
City of Yorba Linda Environmental Consistency Analysis
99 Upon discovery of any Tribal Cultural Resources, construction activities shall cease in the immediate vicinity of the find (not less than the surrounding 50 feet) until the find can be assessed. All Tribal Cultural Resources unearthed by Project activities shall be evaluated by the qualified archaeologist and Tribal monitor approved by the Consulting Tribe. If the resources are Native American in origin, the Consulting Tribe will retain it/them in the form and/or manner the Tribe deems appropriate, for educational, cultural and/or historic purposes. Work may continue on other parts of the Project site while evaluation and, if necessary, mitigation takes place (CEQA Guidelines Section 15064.5[f]). If a non-Native American resource is determined by the qualified archaeologist to constitute a “historical resource” or “unique archaeological resource,” time allotment and funding sufficient to allow for implementation of avoidance measures, or appropriate mitigation, must be available.

The treatment plan established for the resources shall be in accordance with CEQA Guidelines Section 15064.5(f) for historical resources and PRC Sections 21083.2(b) for unique archaeological resources.

Proposed Project Applicability: MM 4.10-1 is applicable to the proposed Project and will be incorporated into the MMRP.

Page 658 of 2028 ends

19081 Yorba Linda Boulevard Residential Project
City of Yorba Linda Environmental Consistency Analysis
100

5.11.WILDFIRE
If located in or near State Responsibility Areas
or lands classified as very high fire hazard
severity zones, would the project:

Substantial
Change in
Project or
Circumstances
Resulting in
New
Significant
Effects
New
Information
Showing
Greater
Significant
Effects than
Previous EIR
New
Information
Identifying
New
Mitigation
or
Alternative
to Reduce
Significant
Effect is
Declined
Minor
Technical
Changes
or
Additions
No New
Impact/
No
Impact
a) Substantially impair an adopted emergency
response plan or emergency evacuation plan?
b) Due to slope, prevailing winds, and other
factors, exacerbate wildfire risks, and thereby
expose project occupants to, pollution
concentrations from a wildfire or the uncontrolled
spread of a wildfire?
c) Require the installation or maintenance of
associated infrastructure (such as roads, fuel
breaks, emergency water sources, power lines,
or other utilities) that may exacerbate fire risk or
that may result in temporary or ongoing impacts
to the environment?
d) Expose people or structures to significant risks,
including downslope or downstream flooding or
landslides, as a result of runoff, post-fire slope
instability, or drainage changes?
Summary of Impacts Identified in the HEIP PEIR
The HEIP PEIR discussed impacts related to wildfire under Section 4.11. The HEIP PEIR notes that the City has an adopted Emergency Operation Plan (EOP) that establishes emergency organization, assigns tasks, specifies policies and general procedures, and provides for coordination of planning efforts of the various emergency staff and service elements. An increase in dwelling units under the HEIP could lead to changes in mobility patterns which could potentially impair implementation of or physically interfere with the City of Yorba Linda or Orange County’s emergency response or evacuation plans. However, future projects would be required to implement MM 4.11-1, which would ensure the proper evaluation of emergency evacuation during wildfires. With implementation of the required mitigation and General Plan goals and policies, the project’s potential impacts to an adopted emergency response or emergency evacuation route would be reduced to less than significant.

Future development located within a Very High FHSZ would add people and structures that could be at risk from a wildfire, resulting in potentially significant impacts. However, implementation of MM 4.11-2 would ensure the project’s potential impacts to wildland fire hazards be mitigate through the installation of fire

Page 659 of 2028 ends

19081 Yorba Linda Boulevard Residential Project
City of Yorba Linda Environmental Consistency Analysis
101
systems, fire-resistant landscaping and appropriate defensible space around structures, and water availability to serve to the project site.

The HEIP PEIR determined the need for installation and maintenance of new infrastructure (such as roads, fuel breaks, emergency water resources, power lines, or other utilities) for future development projects would be evaluated as part of the discretionary permit review process. Therefore, impacts would be less than significant.

The HEIP PEIR determined impacts related to directly or indirectly causing potential substantial risks, including landslides, as a result of runoff, post-fire instability or drainage change would be less than significant because all future implementing projects would be required to have a site-specific geotechnical investigation, which would ensure that each development is engineered and constructed to maximize stability and preclude safety hazards to on-site areas. Additionally, all future development would be required to comply with City’s floodplain management regulations prepare a WQMP which would reduce runoff from construction and identify BMPs for runoff controls and treatments. Thus, impacts would be less than significant.

Impacts Associated with the Proposed Project
a) Substantially impair an adopted emergency response plan or emergency evacuation plan? No New Impact.

According to the HEIP PEIR Figure 4.11-1, Fire Hazard Severity Zones within the City, and the CAL FIRE Hazard Severity Zone map, the Project site not located within a State Responsibility Area (SRA) or a VHFHSZ (City of Yorba Linda, 2022; CAL FIRE, 2025). The Project site does not contain any emergency facilities, nor does it serve as an emergency evacuation route. Direct access to the Project site would be provided via one driveway on Yorba Linda Boulevard. The Project is required to design and construct internal access and provide fire suppression facilities (e.g., hydrants and sprinklers) in conformance with the YLMC, and OCFA would review the development plans prior to approval to ensure adequate emergency access pursuant to the requirements in Section 503 of the CFC (Title 24, California Code of Regulations, Part 9, included in the YLMC as Chapter 15.08. As a result, the proposed Project would not impair an adopted emergency response plan or emergency evacuation plan and would not result in new impacts. As such, the proposed Project is consistent with the findings of the HEIP PEIR and no new impact would occur. b) Due to slope, prevailing winds, and other factors, exacerbate wildfire risks, and thereby expose project occupants to pollutant concentrations from a wildfire or the uncontrolled spread of a wildfire?
No New Impact.

As described in the previous response, the Project site is not located within an SRA or a VHFHSZ. The Project site is relatively flat and the areas within the Project’s vicinity do not contain hillsides or other factors that could exacerbate wildfire risks. Therefore, the Project would not result in new or increased impacts related to exposure of people or structures to significant risk involving wildland fires. As such, the proposed Project is consistent with the findings of the HEIP PEIR and now new impact would occur. c) Require the installation or maintenance of associated infrastructure (such as roads, fuel breaks, emergency water sources, power lines or other utilities) that may exacerbate fire risk or that may result in temporary or ongoing impacts to the environment? No New Impact.

As described in the previous responses, the Project site is not within an SRA or a VHFHSZ. The Project site is located within an urbanized area within the City of Yorba Linda. The Project does not involve any new

Page 660 of 2028 ends

19081 Yorba Linda Boulevard Residential Project
City of Yorba Linda Environmental Consistency Analysis
102
infrastructure (such as roads, fuel breaks, emergency water sources, power lines, or other utilities) that may exacerbate fire risks or result in other impacts to the environment. Therefore, the Project would result in no new or increased impacts. As such, the proposed Project is consistent with the findings of the HEIP PEIR and now new impact would occur.
d) Expose people or structures to significant risks, including downslope or downstream flooding or landslides, as a result of runoff, post-fire slope instability, or drainage changes? No New Impact.

As described in the previous responses, the Project site is not within an SRA or VHFHSZ. The Project would not result in substantial changes to the existing drainage pattern of the site. Additionally, the Project site is flat and is not susceptible to landslides. Likewise, areas adjacent to the Project site are relatively flat urban sites that do not contain hillsides or other factors that would expose people or structures to flooding or landslides as a result of runoff, post-fire slope instability, or drainage changes. The Project would not generate slopes and would connect to existing drainage facilities. Therefore, the Project would result in no new or increased impacts related to significant risks, including downslope or downstream flooding or landslides, as a result of runoff, post-fire slope instability, or drainage changes. As such, the proposed Project is consistent with the findings of the HEIP PEIR and now new impact would occur.

Conclusion
Based on the foregoing information, none of the conditions identified in State CEQA Guidelines Section 15162 that would trigger the need to prepare a subsequent or supplemental EIR or other environmental document to evaluate project impacts or mitigation measures exist regarding wildfire. There have not been (1) changes related to development of the Project site that involve new significant environmental effects or a substantial increase in the severity of previously identified effects; (2) substantial changes with respect to the circumstances under which development of the Project site is undertaken that require major revisions of the HEIP PEIR due to the involvement of new significant environmental effects or a substantial increase in the severity of previously identified effects; or (3) the availability of new information of substantial importance relating to significant effects or mitigation measures or alternatives that were not known and could not have been known when the HEIP PEIR was adopted as completed.

HEIP PEIR Mitigation Measures
MM 4.11-1 Prior to issuance of a grading permit for sites within or adjacent to a Very High FHSZ, the project applicant shall prepare a Fire Evacuation Analysis. The Fire Evacuation Analysis shall assess the time required for emergency evacuation under Existing and Existing with Project Conditions, assuming a worst case, wind-driven fire. The Fire Evacuation Analysis shall also identify how much the project would increase evacuation times by; how long it would take residents to evacuate; and how emergency response times would be affected by a mass evacuation under multiple scenarios. The Fire Evacuation Analysis shall be subject to the review and approval from the City of Yorba Linda and OCFA. The analysis shall demonstrate how the Project would not impair or physically interfere with an adopted emergency response plan or emergency evacuation plan.

Proposed Project Applicability: MM 4.11-1 is not applicable to the proposed Project because the Project site is not located within or adjacent to a Very High FHSZ.

Page 661 of 2028 ends

19081 Yorba Linda Boulevard Residential Project
City of Yorba Linda Environmental Consistency Analysis
103
MM 4.11-2 Prior to issuance of a grading permit for sites within or adjacent to a Very High FHSZ, the project applicant shall prepare a Fire Protection Plan (FPP). Prior to preparation of an FPP, the Project proponent shall coordinate with OCFA to ensure that modeling of the FPP and design of the project is appropriate to meet the requirements and standards of the OCFA.

The FPP shall be subject to the review and approval from the City of Yorba Linda and OCFA. The FPP shall assess a project’s compliance with current regulatory codes and ensure that impacts resulting from wildland fire hazards have been adequately mitigated. The FPP shall also specifically identify the need for fire systems, water availability, construction requirements, and fire-resistant landscaping i.e. fuel modification zones), and appropriate defensible space around structures.

Proposed Project Applicability: MM 4.11-2 is not applicable to the proposed Project because the Project site is not located within or adjacent to a Very High FHSZ.

Page 662 of 2028 ends

19081 Yorba Linda Boulevard Residential Project
City of Yorba Linda Environmental Consistency Analysis
104

6. CLASS 32 DETERMINATION
As described under Section 1.2 of this document, in addition to meeting the requirements of CEQA Guidelines Section 15168 and 15162, the Project would also qualify for a Class 32 In-Fill Exemption under CEQA Guidelines Section 15332. The analysis below provides substantial evidence that the proposed Project properly qualifies for an exemption under CEQA Guidelines Section 15332 (i.e., Class 32) and, as a result, would not have a significant effect on the environment. Additionally, the analysis shows there are no exceptions to qualifying for the Categorical Exemption, as identified in CEQA Guidelines Section 15300.2.

6.1. CLASS 32 INFILL EXEMPTION
CEQA Guidelines Section 15332 defines the Class 32 Infill Exemption as a project that meets the following five requirements:
a. General Plan and Zoning Consistency: The project is consistent with the applicable General Plan designation and all applicable General Plan policies as well as with applicable zoning designation and regulations.

The Project sites has a General Plan land use designation of Residential High (R-H) and a zoning designation of Residential Multiple-Family 20 (RM-20). The R-H General Plan land use designation is intended for residential development with a density of 4-30 du/ac. The RM-20 zoning district is intended to promote the development of multi-family rental as well as ownership dwelling units up to 20 units per acre. The proposed Project would construct 62 attached, townhome residential units on the 2.64-acre site, which would result in a density of 23 du/ac. The Project proposes to set aside three of the 62 proposed units, or five percent of the total units, for very-low income households. As set forth in YLMC Section 18.19.040, restricting 5 percent of the proposed units for very-low income households would afford the Project a 20 percent density bonus. mote the development of multi-family rental as well as ownership dwelling units up to 20 units per acre. Table 6-1 shows the proposed Project’s consistency with the RM-20 development standards, as well as applicable waivers. As shown, the Project would meet all the requisite development standards, including lot size, height, setback, and parking requirements with applicable waivers. Therefore, the proposed Project would be consistent with the applicable development standards.

Table 6-1: Project Consistency with Zoning Standards
Development Standard RM-20 Requirement Proposed Project Minimum lot size 1 acre Consistent. The Project site is 2.64- acres.

Maximum lot coverage 65 percent Consistent. 40 percent
Maximum building height 40 feet or 3 stories, whichever is less
Consistent. 35 feet
Minimum front yard setback 20 feet Consistent. 20 feet
Minimum side yard setback
(interior)
5 feet Consistent. 5 feet
Minimum rear yard setback 20 feet Consistent. 20 feet
Minimum dwelling size Studio = 550 sq. ft.
1 BR = 675 sq. ft.
2 BR = 700 sq. ft.

Consistent. The floor plans would
provide options for three to four
bedrooms, three to four bathrooms,

Page 663 of 2028 ends

19081 Yorba Linda Boulevard Residential Project
City of Yorba Linda Environmental Consistency Analysis
105
3 BR = 900 sq. ft. and would range from 1,363 to
1,639 SF.

Minimum parking per dwelling unit1 3 Bedroom: 1.5 space/du 4 Bedroom: 2.5 spaces/du
Residential parking required: 122
spaces
Consistent. Waiver of minimum
parking requirements per provision
of income restricted units. The
Project proposes 137 parking
spaces.
1 Parking standards per State Density Bonus Law
Source: YLMC, Table 18.10-2, Residential Development Standards The Project is permitted subject to a VTTM, Density Bonus, and Design Review from the City of Yorba Linda. As demonstrated throughout this document, the Project is consistent with the site’s land use and zoning designation and would not conflict with any of the applicable General Plan goals and policies nor would it conflict with the Zoning Code. Therefore, the proposed Project meets the criteria of CEQA Guidelines Section 15332(a).
b. Project Location, Size, and Context: The proposed development occurs within city limits on a project site of no more than 5 acres substantially surrounded by urban uses.

The 2.64-acre Project site is located on Yorba Linda Boulevard in the City of Yorba Linda. The Project site is surrounding by single family residential homes to the north, Jessamyn West Park to the east, a single-family residential home to the southeast, Yorba Linda Boulevard to the south, and a synagogue with a learning center to the west. As the Project site is less than five acres and surrounded by urban uses, it meets the criteria of CEQA Guidelines Section 15332(b) c. Endangered, Rare, or Threatened Species: The project site has no value as habitat for endangered, rare, or threatened species.

As discussed in Section 5.2, Biological Resources, the Project site does not contain habitat for specialstatus plant species or plant communities. The BRA prepared for the Project site determined that the site has a high potential to support Cooper’s hawk and sharp-shinned hawk. However, the Project would require compliance with the MBTA, which prohibits the take of nesting birds and recommends preconstruction nesting bird surveys to be conducted if construction occurs during the nesting bird season between February through August. In order to comply with the MBTA, the Project Applicant/Contractor would conduct pre-construction nesting bird surveys three days prior to vegetation removal during the nesting bird season (generally February 1 through September 15 (PDF BIO-1). Therefore, with adherence to the provisions of the MBTA, potential impacts related to nesting birds, including Cooper’s hawk and sharp-shinned hawk, would be less than significant. Therefore, the proposed Project meets the criteria of CEQA Guidelines Section 15332(c).
d. Significant Effects: Approval of the project would not result in any significant effects relating to traffic, noise, air quality, or water quality.

As discussed in Section 5, Environmental Analysis, the proposed Project would not result in any significant impacts related to traffic, noise, air quality, or water quality. Therefore, the proposed Project meets the criteria of CEQA Guidelines Section 15332(d).
e. Utilities: The site can be adequately served by all required utilities and public services.

The Project site is currently developed with a single-family residence that is served by existing utilities and public services. The Project would be served by Yorba Linda Water District for water and sewer services. The Project would install new 8-inch private water lines on-site which would connect to the existing 8-inch domestic water main in Yorba Linda Boulevard. Additionally, the Project would install

Page 664 of 2028 ends

19081 Yorba Linda Boulevard Residential Project
City of Yorba Linda Environmental Consistency Analysis
106
new 8-inch private sewer lines on-site which would connect to the existing 8-inch sanitary sewer within the Yorba Linda Boulevard median. Project drainage infrastructure would connect to a parkway drain in Yorba Linda Boulevard.

Additionally, SCE would provide electrical service for the Project. There is an existing overhead electrical line that extends halfway over the eastern portion of the Project site and connects to an existing power pole located within the central area of the eastern half of the site. Both the existing overhead line and power pole would be removed. The Project would install underground electric lines that would connect to existing SCE infrastructure in adjacent roadways. No natural gas use is proposed for the Project.

Additionally, as described under section 5.7, Public Services, OCFA and OCSD have adequate capacity to serve the Project site. Therefore, the proposed Project meets the criteria of CEQA Guidelines Section 15332(e).

6.2. EXEMPTION EXCEPTIONS
In addition to meeting the five requirements stated above, the CEQA Guidelines Section 15300.2 provides specific instances where exceptions apply to a project that would otherwise meet the requirements for an exemption. These exceptions are:
a. Criterion 1500.2(a) – Location: The location exception states that Classes 3 (New Construction of Small Structures), 4 (Minor Alterations to Land), 5 (Alterations in Land Use Limitations), 6 (Information Collection), and 11 (Accessory Structures) are qualified by consideration of where the project is to be located – a project that is ordinarily insignificant in its impact on the environment may in a particularly sensitive environment be significant. Therefore, these classes are considered to apply all instances, except where the project may impact on an environmental resource of hazardous or critical concern where designated, precisely mapped, and officially adopted pursuant to law by federal, State, or local agencies.

The Project does not qualify for an exemption under Classes 3, 4, 5, 6 or 11. The Project is located within an urban developed area and is not located within a sensitive environment. In addition, the Project would not result in any impacts on an environmental resource of hazardous or critical concern. Therefore, the exception under criterion 15300.2(a) is not applicable b. Criterion 1500.2(b) – Cumulative Impact: All exemptions for these classes are inapplicable when the cumulative impact of successive projects of the same type in the same place, over time is significant.

The proposed Project would redevelop a site that is currently developed with an existing single-family residence. The Project site is already served by utilities and public services, as well as transportation.

Any construction effects would be temporary, confined to the Project vicinity, and reduced to a less-thansignificant level by implementing existing applicable regulatory requirements. Therefore, the Project’s impacts would be less than significant and not cumulatively considerable. No successive projects of the same or similar use within the vicinity of the Project are known or expected to occur over time that would result in cumulatively considerable impacts. Furthermore, as discussed throughout this justification document, the proposed Project would not result in significant environmental impacts that would be capable of combining with impacts from other cumulative projects to result in a cumulative impact.

Therefore, the exception under CEQA Guidelines Section 15300.2(b) does not apply to the Project. c. Criterion 1500.2(c) – Significant Effects: A Categorical Exemption shall not be used for an activity where there is a reasonable possibility that the activity will have a significant effect on the environment due to unusual circumstances.

Page 665 of 2028 ends

19081 Yorba Linda Boulevard Residential Project
City of Yorba Linda Environmental Consistency Analysis
107
There are no known unusual circumstances that are applicable to the Project, which may result in a significant effect on the environment. The proposed Project consists of the development of 62 attached, townhome residential units on a site that is currently developed with a single-family residence and is already served by utilities and transportation. The Project site would also be consistent with the City’s General Plan and the Municipal Code. Thus, provision of a professional office building would not introduce a new activity to the area that could result in a significant effect on the environment. Therefore, the exception under CEQA Guidelines Section 15300.2(c) does not apply to the Project. d. Criterion 1500.2(d) – Scenic Highways: A Categorical Exemption shall not be used for a project which may result in damage to scenic resources, including but not limited to, trees, historic buildings, rock outcroppings, or similar resources, within a highway officially designated as a State scenic highway. This does not apply to improvements which are required as mitigation by an adopted negative declaration or certified EIR.

As described under Section 4.2, there are no State, County, or locally designated scenic highways in the City. therefore, the exception under CEQA Guidelines Section 15300.2(d) does not apply to the Project. e. Criterion 1500.2(e) – Hazardous Waste Sites: A Categorical Exemption shall not be used for a project located on a site which is included on any list complied pursuant to Section 65962.5 of the Government Code.

As described under Section 4.2, the HEIP PEIR determined none of the housing opportunity sites are identified on any hazardous materials databases compiled pursuant to Government Code Section 65962.5. Therefore, the exception under CEQA Guidelines Section 15300.2(e) does not apply to the Project.
f. Criterion 1500.2(f) – Historical Resources: A Categorical Exemption shall not be used for a project which may cause a substantial adverse change in the significance of a historical resource.

As described under Section 4.2, the Project site does not contain any historical resources. Therefore, the exception under CEQA Guidelines Section 15300.2(f) does not apply to the Project.

Conclusion
On the basis of the evidence provided above, the proposed Project is eligible for a Class 32 Categorical Exemption in accordance with Section 15332 of the CEQA Guidelines. Because the proposed Project meets the criteria for categorically exempt development projects listed in CEQA Guidelines Section 15332 and it would not have a significant effect on the environment, this analysis finds that a Notice of Exemption may be prepared for the Project.

Page 666 of 2028 ends

19081 Yorba Linda Boulevard Residential Project
City of Yorba Linda Environmental Consistency Analysis
108

7. REFERENCES
Airport Land Use Commission. (2019). Airport Environs Land Use Plan for Fullerton Municipal Airport.

Retrieved July 11, 2025, from https://files.ocair.com/media/2021- 02/AELUP%20for%20FMA%2005092019.pdf?VersionId=Pe0mNdYdt9RPkWpfPFbhCmkVI4zej Gxs
Alta California Geotechnical Inc. (n.d.). Geotechnical Investigation 19081 Yorba Linda Boulevard, City of Yorba Linda, California. (Appendix A).

California Department of Conservation. (November 1, 2024). Earthquake Zones of Required Investigation.

Retrieved May 21, 2025, from
https://maps.conservation.ca.gov/cgs/informationwarehouse/eqzapp/ California Department of Finance (CDOF). (May 2025). E-5 Population and Housing Estimates for Cities, Counties, and the State, 2020-2025. Retrieved July 14, 2025, from https://dof.ca.gov/forecasting/demographics/estimates/e-5-population-and-housing-estimatesfor-cities-counties-and-the-state-2020-2025/ California Department of Forestry and Fire Protection (CAL FIRE). (May 2025). Fire Hazard Severity Zones.

Retrieved June 10, 2025, from https://osfm.fire.ca.gov/what-we-do/community-wildfirepreparedness-and-mitigation/fire-hazard-severity-zones California Department of Transportation (Caltrans). (2020a). Technical Noise Supplement to the Traffic Noise Analysis Protocol. Retrieved July 29, 2025, from https://dot.ca.gov/-/media/dotmedia/programs/environmental-analysis/documents/env/traffic-noise-protocol-april-2020- a11y.pdf
California Department of Transportation (Caltrans). (2020b). Transportation and Construction Vibration Guidance Manual. Retrieved July 29, 2025, from https://dot.ca.gov/-/media/dotmedia/programs/environmental-analysis/documents/env/tcvgm-apr2020-a11y.pdf City of Yorba Linda. (2016a). 2016 General Plan Land Use Map. Retrieved May 21, 2025, from https://www.yorbalindaca.gov/DocumentCenter/View/465/2016-General-Plan-Land-Use-MapPDF?bidId= City of Yorba Linda. (2016b). City of Yorba Linda General Plan Draft Environmental Impact Report.

Retrieved June 17, 2025, from
https://www.yorbalindaca.gov/DocumentCenter/View/510/Yorba-Linda-2016-General-PlanDEIR-PDF?bidId= City of Yorba Linda. (2016c). 2016 Yorba Linda General Plan. Retrieved August 12, 2025, from https://www.yorbalindaca.gov/337/General-Plan
City of Yorba Linda. (February 12, 2019). City of Yorba Linda Official Zoning Map. Retrieved May 21, 2025, from https://www.yorbalindaca.gov/DocumentCenter/View/466/City-of-Yorba-LindaZoning-Map-PDF City of Yorba Linda. (June 2022). Draft Program Environmental Impact Report SCH No., 2022040574.

Retrieved May 21, 2025, from https://www.yorbalindaca.gov/341/Environmental-Documents C&V Consulting, Inc. (March 2025a). Preliminary Hydrology Study Tentative Tract Map No. 19389, 19081 Yorba Linda Blvd City of Yorba Linda, County of Orange. (Appendix D).

Page 667 of 2028 ends

19081 Yorba Linda Boulevard Residential Project
City of Yorba Linda Environmental Consistency Analysis
109
C&V Consulting, Inc. (March 2025b). Preliminary Water Quality Management Plan (PWQMP). (Appendix E).

ELMT Consulting. (June 27, 2025). Biological Resources Assessment for the Proposed Project Located at 19081 Yorba Linda Boulevard in the City of Yorba Linda, Orange County, California. (Appendix G).

EPD Solutions, Inc. (August 4, 2025a). Air Quality and Greenhouse Gas Impact Analysis for the 19081 Yorba Linda Boulevard Residential Project. (Appendix F).

EPD Solutions, Inc. (August 2025b). 19081 Yorba Linda Boulevard Residential Project Noise and Vibration Impact Analysis. (Appendix H).

EPD Solutions, Inc. (May 28, 2025c). Vehicle Miles Traveled (VMT) Screening Analysis. (Appendix I).

Federal Emergency Management Agency (FEMA). (December 3, 2009). Flood Insurance Rate Map Number 06059C0068J. Retrieved June 17, 2025, from
https://msc.fema.gov/portal/search?AddressQuery=19081%20Yorba%20Linda%20Blvd%2C% 20Yorba%20Linda%2C%20CA
Federal Interagency Committee on Noise. (1992). Federal Agency Review of Selected Airport Noise Analysis Issue. Retrieved June 9, 2025, from
https://www.faa.gov/sites/faa.gov/files/reports_noise_analysis.pdf Southern California Association of Governments (SCAG). (April 4, 2024). Demographics & Growth Forecast.

Retrieved July 14, 2025, from https://scag.ca.gov/sites/default/files/2024-05/23-2987-trdemographics-growth-forecast-final-040424.pdf South Coast Air Quality Management District (SCAQMD). (2010). Minutes of the GHG CEQA Significance Threshold Stakeholder Working Group #15. Retrieved August 12, 2025, from http://www.aqmd.gov/docs/default-source/ceqa/handbook/greenhouse-gases-(ghg)-ceqasignificance-thresholds/year-2008-2009/ghg-meeting-15/ghg-meeting-15-minutes.pdf Stantec. (April 20, 2022a). Phase I Environmental Site Assessment 19081 Yorba Linda Boulevard Yorba Linda, California 92886. (Appendix B).

Stantec. (July 7, 2022b). Phase II Environmental Site Assessment 19081 Yorba Linda Boulevard Yorba Linda, California 92886. (Appendix C).

Page 668 of 2028 ends

Corona Office
Phone: 951.509.7090

CITY VENTURES DRAFT
3121 Michelson Drive, Suite 150 Project No. 1-0539
Irvine, California 92612
Attention: Mr. Patrick Chien
Subject: GEOTECHNICAL INVESTIGATION
19081 Yorba Linda Boulevard,
City of Yorba Linda, California
Dear Mr. Chien:

Alta California Geotechnical, Inc. (Alta) is pleased to present this geotechnical investigation for the proposed development at 19081 Yorba Linda Boulevard, in the City of Yorba Linda, Orange County, California. This report is based upon a recent subsurface investigation conducted by Alta, laboratory testing, a review of published geologic maps, and Alta’s staff’s experience with similar projects in this vicinity.

Alta’s review of the data indicates that the proposed development is feasible, from a geotechnical perspective, provided that the recommendations presented in this report are incorporated into the grading and improvement plans and implemented during site development.

Included in this report are:
 Discussion of the site geotechnical conditions.
 Recommendations for remedial and site grading, including unsuitable soil removals  Geotechnical site construction recommendations
 Preliminary foundation design parameters
 Preliminary Infiltration testing
 Estimate shrink/swell parameters

Page 669 of 2028 ends

Project Number 1-0568 Page ii
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.

If you have any questions or should you require any additional information, please contact the undersigned at (951) 509-7090. Alta appreciates the opportunity to provide geotechnical consulting services for your project.

Sincerely,
Alta California Geotechnical, Inc. Reviewed By:
________DRAFT________________________
SCOTT A. GRAY/RGE 2857
Reg. Exp.: 12-31-26
Registered Geotechnical Engineer
President
_________DRAFT_________________________
FRANK ECHENIQUE/CEG 2134
Reg. Exp.: 7-31-26
Certified Engineering Geologist
Distribution: (1) Addressee
LAM: SAG: eg-1-0568 (DRAFT, January 2025) Geotechnical Investigation,CV Yorba Linda)

Page 670 of 2028 ends

Project Number 1-0568 Page iii
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.

1.0 INTRODUCTION ................................................................................................................... 1

1.1 Purpose ......................................................................................................................... 1

1.2 Scope of Work ............................................................................................................... 1

1.3 Report Limitations ......................................................................................................... 2

2.0 PROJECT DESCRIPTION ........................................................................................................ 2

2.1 Site Location and Existing Conditions ............................................................................ 2

2.2 Proposed Development ................................................................................................. 2

3.0 SITE INVESTIGATION ............................................................................................................ 3

3.1 Current Subsurface Investigation .................................................................................. 3

3.2 Infiltration Testing ......................................................................................................... 3

4.0 GEOLOGIC CONDITIONS ...................................................................................................... 4

4.1 Geologic and Geomorphic Setting ................................................................................. 4

4.2 Stratigraphy ................................................................................................................... 4

4.2.1 Very Old Alluvial Fan Deposits (Map symbol Qvof) ............................................... 4

4.3 Geologic Structure ......................................................................................................... 4

4.3.1 Tectonic Framework .............................................................................................. 4

4.3.2 Regionally Mapped Active Faults ........................................................................... 5

4.3.3 Geologic Structures ............................................................................................... 5

4.4 Groundwater ................................................................................................................. 5

4.5 Earthquake Hazards ...................................................................................................... 5

4.5.1 Local and Regional Faulting ................................................................................... 6

4.5.2 Seismicity ............................................................................................................... 6

4.5.3 Surface Rupture ..................................................................................................... 6

4.5.4 Liquefaction ........................................................................................................... 6

4.5.5 Dry Sand Settlement .............................................................................................. 7

4.6 Regional Subsidence ...................................................................................................... 7

5.0 ENGINEERING PROPERTIES AND ANALYSIS ......................................................................... 7

5.1 Materials Properties ...................................................................................................... 7

5.1.1 Excavation Characteristics ..................................................................................... 7

5.1.2 Compressibility ...................................................................................................... 8

5.1.3 Moisture ................................................................................................................ 8

5.1.4 Hydro-Consolidation .............................................................................................. 8

5.1.5 Expansion Potential ............................................................................................... 8

5.1.6 Earthwork Adjustments ......................................................................................... 9

5.1.7 Chemical Analyses ................................................................................................. 9

5.2 Engineering Analysis ...................................................................................................... 9

5.2.1 Bearing Capacity and Lateral Earth Pressures ...................................................... 10

Page 671 of 2028 ends

Project Number 1-0568 Page iv
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.

6.0 CONCLUSIONS AND RECOMMENDATIONS ........................................................................ 10

6.1.1 Site Preparation ................................................................................................... 10

6.1.2 Unsuitable Soil Removals .................................................................................... 10

6.2 General Earthwork Recommendations........................................................................ 11

6.2.1 Compaction Standards ........................................................................................ 11

6.2.2 Groundwater/Seepage ........................................................................................ 12

6.2.3 Documentation of Removals ............................................................................... 12

6.2.4 Treatment of Removal Bottoms .......................................................................... 12

6.2.5 Fill Placement ...................................................................................................... 12

6.2.6 Moisture Content ................................................................................................ 13

6.2.7 Mixing .................................................................................................................. 13

6.2.8 Import Soils ......................................................................................................... 13

6.2.9 Utility Trenches ................................................................................................... 13

6.2.9.1 Excavation ............................................................................................................. 13

6.2.9.2 Backfill ................................................................................................................... 14

6.2.10 Backcut Stability .................................................................................................. 15

6.3 Storm Water Infiltration Systems ................................................................................ 15

6.4 Boundary Conditions ................................................................................................... 16

7.0 DESIGN CONSIDERATIONS ................................................................................................. 16

7.1 Structural Design ......................................................................................................... 16

7.1.1 Foundation Design ............................................................................................... 17

7.1.1 Conventional Foundation Systems ...................................................................... 17

7.1.2 Post-Tensioned Slabs/Foundation Design Recommendations ............................. 18

7.2 Moisture Barrier .......................................................................................................... 19

7.3 Seismic Design ............................................................................................................. 20

7.4 Block Walls .................................................................................................................. 21

7.5 Footing Excavations ..................................................................................................... 21

7.6 Retaining Wall Design .................................................................................................. 21

7.7 Exterior Slabs and Walkways ....................................................................................... 23

7.7.1 Subgrade Compaction ......................................................................................... 23

7.7.2 Subgrade Moisture .............................................................................................. 23

7.7.3 Concrete Slab Thickness ...................................................................................... 23

7.7.4 Concrete Slab Reinforcement .............................................................................. 23

7.7.5 Control Joints ....................................................................................................... 24

7.8 Concrete Design .......................................................................................................... 24

7.9 Corrosion ..................................................................................................................... 24

7.10 Pavement Design ......................................................................................................... 25

7.11 Site Drainage ............................................................................................................... 26

Page 672 of 2028 ends

Project Number 1-0568 Page v
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.

8.0 LOT MAINTENANCE ........................................................................................................... 26

8.1 Lot Drainage ................................................................................................................ 26

8.2 Burrowing Animals ...................................................................................................... 27

9.0 FUTURE PLAN REVIEWS ..................................................................................................... 27

10.0 CLOSURE ...................................................................................................................... 27

10.1 Geotechnical Review ................................................................................................... 27

10.2 Limitations ................................................................................................................... 28 APPENDIX A – References
APPENDIX B – Subsurface Investigation
APPENDIX C – Laboratory Testing
APPENDIX D – Maintenance and Improvement Considerations APPENDIX E – Earthwork Specifications
APPENDIX F – Grading Details

Page 673 of 2028 ends

Project Number 1-0539 Page 1
July 24, 2024
ALTA CALIFORNIA GEOTECHNICAL, INC.

1.0 INTRODUCTION
The following report presents Alta’s findings, conclusions, and geotechnical recommendations for the proposed development of located in the City of Yorba Linda, California.

1.1 Purpose
The purpose of this report is to examine the existing geotechnical conditions and evaluate their impacts on the proposed development. This report is suitable for submittal to governing agencies and for use as a bid document.

1.2 Scope of Work
Alta’s Scope of Work for this geotechnical investigation included the following:
 Review of the referenced literature, maps, and aerial photos (Appendix A).
 Site geologic mapping.
 Excavating, logging, and sampling of five (5) hollow stem auger borings to a maximum depth of approximately 51 feet below existing grade (Appendix B).
 Drill two (2) shallow additional borings for infiltration study and perform preliminary infiltration testing.
 Conducting laboratory testing on samples obtained during our investigation (Appendix C).
 Evaluating engineering geologic and geotechnical engineering data, including laboratory data, to develop recommendations for site remedial grading, import soil, foundations and utilities.
 Preparing this report and accompanying exhibits.

Page 674 of 2028 ends

Project Number 1-0568 Page 2
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.

1.3 Report Limitations
The conclusions and recommendations in this report are based on the information generated during this investigation and our review of the referenced reports. The materials adjacent to or beneath those observed may have different characteristics than those observed, and no representations are made as to the quality or extent of the materials not observed.

2.0 PROJECT DESCRIPTION

2.1 Site Location and Existing Conditions
The rectangular shaped ±3.9-acre site is relatively flat and consists of singlefamily residences. The site is bounded to the north by a residential property, to the west by a residential property and synagogue, to the east by a park, and to the south by Yorba Linda Boulevard.

Historic aerial images of the site are available as far back as 1946 and indicate the site and surrounding area was comprised of citrus groves. By 1963 the single-family residences were built. The site has remained largely unchanged since, with the exception of removal of some of the trees.

Our literature review indicates that the site is underlain by mid to early Pleistocene age very old alluvial fan deposits. No known active faults have been mapped at the site or in the immediate site vicinity.

2.2 Proposed Development
Alta anticipates that the site will be developed to accommodate a multi-family residential development. Alta anticipates that conventional cut-and-fill grading techniques will be used to develop the site for the support of wood-frame construction with shallow foundations and reinforced concrete slabs-on-grade, and associated improvements.

Page 675 of 2028 ends

Project Number 1-0568 Page 3
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.

3.0 SITE INVESTIGATION

3.1 Current Subsurface Investigation
Alta conducted a subsurface investigation on December 9, 2024, consisting of the drilling, logging, and select sampling of five (5) hollow-stem auger borings up to a maximum depth of 51 feet below the ground surface (bgs). In addition, two (2) shallow borings (5 and 10 feet deep) were advanced to conduct preliminary infiltration testing. The locations of exploratory borings are shown on Plate 1 and the logs are presented in Appendix B.

Laboratory testing was performed on ring and bulk samples obtained during the field investigation. A brief description of the laboratory test procedures and the test results are presented in Appendix C.

3.2 Infiltration Testing
Infiltration testing was performed by Alta on December 10, 2024, utilizing percolation methods in accordance with County of Orange Storm Water Standards. Percolation rates were converted to infiltration rates utilizing the Porchet method. The resulting field infiltration rates, with no factor of safety, are presented below in Table 3-1. Recommendations for infiltration BMP design are presented in Section 6.3.

Table 3-1
Summary of Infiltration Testing
(No Factor of Safety)
Test Designation P-1 P-2
Approximate Depth of Test 10.0 feet 5.0 feet
Final Time Interval 30 minutes 30 minutes
Tested Infiltration Rate 0.8 in/hr 0.1 in/hr

Page 676 of 2028 ends

Project Number 1-0568 Page 4
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.

4.0 GEOLOGIC CONDITIONS

4.1 Geologic and Geomorphic Setting
Regionally, the site is located in the Peninsular Ranges geomorphic province, which characterizes the southwest portion of Southern California. The Peninsular Ranges province is composed of Mesozoic age plutonic and metamorphic rock, lesser amounts of Tertiary age volcanic and sedimentary rock, and Quaternary age drainage in-fills and minor sediment veneers. The Peninsular Ranges are divisible into northwest-trending sub-blocks that extend south into Baja California and terminate to the north against the Transverse Ranges province.

4.2 Stratigraphy
Based on Alta’s review of geologic literature and our subsurface investigation the project site is underlain by Pleistocene age very old alluvial fan deposits (Dibblee, 2001). The following is a brief description of this geologic unit encountered during this investigation.

4.2.1 Very Old Alluvial Fan Deposits (Map symbol Qvof)
The very old alluvial fan deposits within the site consists primarily of inter-lensed silty sand, clayey sand, sand and gravelly sand that is slightly moist to moist and dense to very dense below. This unit was encountered up to 51 feet below ground surface (bgs).

4.3 Geologic Structure

4.3.1 Tectonic Framework
Jennings (1985) defined eight structural provinces within California that have been classified by predominant regional fault trends and similar fold structure. Within this framework, the subject site is located within the Peninsular Ranges geomorphic province, controlled by the dominant northwest trend of the San Andreas Fault and the subparallel San Jacinto

Page 677 of 2028 ends

Project Number 1-0568 Page 5
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.

Fault, Whittier/Elsinore Fault, and the Newport-Inglewood Fault, all exhibit right lateral strike-slip movement. The closest of these major faults to the site is the Whittier-Elsinore Fault, located 2.1 kilometers from the site. These fault systems have been studied extensively and in a large part control the geologic structure of the region.

4.3.2 Regionally Mapped Active Faults
Active faults in the region, including the Puente Hills Fault (6.8 kilometers from the site, which is a thrust fault, and the Whittier-Elsinore Fault (2.1 kilometers from the site), which is a strike slip fault.

4.3.3 Geologic Structures
Based upon our site investigation and literature review, the onsite subsurface is essentially flat lying sediments that do not appear to be faulted or folded.

4.4 Groundwater
Groundwater was not encountered in any borings during Alta’s recent investigation, to a depth of roughly 51 feet bgs. No nearby groundwater well data is available.

4.5 Earthquake Hazards
The subject site is located in southern California, which is a tectonically active region. The type and magnitude of seismic hazards affecting a site are dependent on the distance to the causative fault and the intensity and magnitude of the seismic event. The seismic hazard may be primary, such as surface rupture and/or ground shaking, or secondary, such as liquefaction and/or ground lurching.

Page 678 of 2028 ends

Project Number 1-0568 Page 6
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.

4.5.1 Local and Regional Faulting
The closest known active fault to the site is the Whittier-Elsinore Fault located 2.1 kilometers from the site. No known active faults exist below the site or in the immediate site vicinity.

4.5.2 Seismicity
Ground shaking hazards caused by earthquakes along other active regional faults exist. The 2022 California Building Code requires usemodified spectral accelerations and velocities for most structural designs.

Seismic design parameters using soil profile types identified in the 2022 California Building Code are presented in Section 7.3.

4.5.3 Surface Rupture
Active faults are not known to exist within the project and a review of Special Publication 42 indicates the site is not within a California State designated earthquake fault zone. Accordingly, the potential for fault surface rupture on the subject site is low.

4.5.4 Liquefaction
Seismic agitation of relatively loose saturated sands, silty sands, and some silts can result in a buildup of pore pressure. If the pore pressure exceeds the overburden stresses, a temporary quick condition known as liquefaction can occur. Liquefaction effects can manifest in several ways including: 1) loss of bearing; 2) lateral spread; 3) dynamic settlement; and 4) flow failure. Lateral spreading has typically been the most damaging mode of failure.

In general, the more recent that a sediment has been deposited, the more likely it will be susceptible to liquefaction. Other factors that must be considered are groundwater, confining stresses, relative density, and the intensity and duration of seismically induced ground shaking.

Page 679 of 2028 ends

Project Number 1-0568 Page 7
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.

Based on the fact that groundwater was not encountered in the borings during our investigation, plus the dense nature of the very old alluvial fan deposits with the removal and re-compaction recommended in this report, the potential for dynamic settlement due to liquefaction is considered to be remote.

4.5.5 Dry Sand Settlement
Dry sand settlement is the process of non-uniform settlement of the ground surface during a seismic event. Based on our subsurface investigation and our removal/recompaction recommendations, the potential for onsite dry sand settlement is anticipated to be nil.

4.6 Regional Subsidence
The site is not located in an area designated as susceptible to subsidence. Upon implementation of the remedial grading recommendations presented herein, the effects of subsidence on the development are considered to be negligible. If subsidence due to groundwater extraction were to occur, it would likely affect the entire region and not result in differential settlement across the site.

5.0 ENGINEERING PROPERTIES AND ANALYSIS

5.1 Materials Properties
Presented herein is a general discussion of the engineering properties of the onsite materials that will be encountered during construction of the proposed project. Descriptions of the soil (Unified Soil Classification System) are presented on the boring logs in Appendix B.

5.1.1 Excavation Characteristics
Based on the data provided from the subsurface investigation, it is our opinion that excavation characteristics across the site are favorable, such that conventional equipment can be utilized.

Page 680 of 2028 ends

Project Number 1-0568 Page 8
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.

5.1.2 Compressibility
The upper portions of the very old alluvial fan deposits are considered compressible and unsuitable to support the proposed improvements.

Recommended removal depths are presented in Section 6.1.2.

5.1.3 Moisture
The moisture content of the very old alluvial fan deposits that will require removal and recompaction as discussed in Section 6.1.2 are typically over-optimum.

5.1.4 Hydro-Consolidation
Hydro-consolidation is the effect of introducing water into soil that is prone to collapse. Upon loading and initial wetting, the soil structure and apparent strength are altered resulting in almost immediate settlement.

That settlement can have adverse impacts on engineered structures, particularly in areas where it is manifested differentially. Differential settlements are typically associated with differential wetting, irregularities in the subsurface soil conditions, or irregular loading patterns.

Based on laboratory testing results presented in Appendix C, there is minimal potential for hydro-collapse in the very old alluvial fan deposits bulks when saturated and under loading.

5.1.5 Expansion Potential
Based on expansion index testing performed during our subsurface investigation (Appendix C), the majority of soils onsite are “very low” to “low” in expansion potential (0≤EI≤50, Appendix C) when tested per ASTM D: 4829.

Page 681 of 2028 ends

Project Number 1-0568 Page 9
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.

5.1.6 Earthwork Adjustments
The values presented in Table 5-1 are deemed appropriate for estimating purposes and may be used to balance earthwork quantities. As is the case with every project, contingencies should be made to adjust the earthwork balance when grading is in-progress and actual conditions are better defined.

TABLE 5-1
Earthwork Adjustment Factors
Geologic Unit Adjustment Factor Range Average
Very old alluvial fan deposits
(within the upper 3 feet) Shrink 6% to 10% 8%
Very old alluvial fan deposits (below
3 feet) Shrink 0% to 4% 2%

5.1.7 Chemical Analyses
Chemical testing was performed on samples of material underlying the proposed site during our subsurface investigation. Soluble sulfate test results indicate that the soluble sulfate concentrations of the soils tested are classified as negligible (Category S0) per ACI 318-14.

Negligible chloride levels were detected in the soils onsite. Based on laboratory results of soluble sulfate, chloride, and pH testing as presented in Appendix C, the onsite soils are classified as “non-corrosive” (Caltrans, 2022). Additional discussions on corrosion are presented in Section 7.9.

5.2 Engineering Analysis
Presented below is a general discussion of the engineering analysis methods that were utilized to develop the conclusions and recommendations presented in this report.

Page 682 of 2028 ends

Project Number 1-0568 Page 10
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.

5.2.1 Bearing Capacity and Lateral Earth Pressures
Ultimate bearing capacity values were obtained using the graphs and formula presented in NAVFAC DM-7.1. Allowable bearing was determined by applying a factor of safety of at least 3 to the ultimate bearing capacity. Static lateral earth pressures were calculated using Rankine methods for active and passive cases. If it is desired to use Coulomb forces, a separate analysis specific to the application can be conducted.

6.0 CONCLUSIONS AND RECOMMENDATIONS
Based on Alta’s findings during our subsurface investigation, the laboratory test results, and our staff’s previous experience in the area, it is Alta’s opinion that the development of the site is feasible from a geotechnical perspective. Presented below are recommendations that should be incorporated into site development and construction plans.

6.1.1 Site Preparation
Vegetation, construction debris, and other deleterious materials are unsuitable as structural fill material and should be disposed of offsite prior to commencing grading/construction. Any septic tanks, seepage pits or wells should be abandoned as per the County of Orange Department of Health Services.

6.1.2 Unsuitable Soil Removals
The upper portions of the very old alluvial fan deposits are compressible and as such, are not suitable to support the proposed structures.

Therefore, it is anticipated that, on average, the upper three (3) to five (5) feet of existing soils will require removal and recompaction, extending a minimum of five (5) feet horizontally outside of the structures. This recommended removal combined with the foundation recommendations

Page 683 of 2028 ends

Project Number 1-0568 Page 11
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.
presented in Section 7.1 should provide suitable support for the proposed structures.

Footings for structures should be underlain by a minimum of two (2) feet of compacted fill. As such, for building pads where unsuitable soil removals do not provide the minimum depth of compacted fill, or where design grades and/or remedial grading activities create cut/fill transitions, the cut and shallow fill portions of the building pads should be over-excavated during grading and replaced with compacted fill.

The Project Geotechnical Consultant should observe the removal bottom prior to placing fill. If unsuitable soils such as undocumented artificial fill is exposed upon the completion of the removals recommended above, additional removals may be required.

For fill areas in parking lots/drive aisles, in general, a minimum removal and recompaction of the upper two (2) feet is recommended, however all undocumented artificial fill shall be removed and recompacted. For cuts greater than two (2) feet in street areas, removals are not required. For cuts less than two (2) feet, the two (2) foot removal and recompaction applies.

Material removed as part of the unsuitable soil removals can be used as artificial fill, provided it is free of deleterious materials.

6.2 General Earthwork Recommendations

6.2.1 Compaction Standards
All fill and processed natural ground shall be compacted to a minimum relative compaction of 90 percent, as determined by ASTM Test Method:

D-1557. Fill material should be moisture conditioned to optimum moisture or above, and as generally discussed in Alta’s Earthwork

Page 684 of 2028 ends

Project Number 1-0568 Page 12
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.

Specification Section presented in Appendix E. Compaction shall be achieved with the use of sheepsfoot rollers or similar kneading type equipment. Mixing and moisture conditioning will be required in order to achieve the recommended moisture conditions.

6.2.2 Groundwater/Seepage
No groundwater was encountered during our subsurface investigation.

Perched water conditions could be encountered depending on the time of year construction occurs.

6.2.3 Documentation of Removals
All removal/over-excavation bottoms should be observed and approved by the project Geotechnical Consultant prior to fill placement.

Consideration should be given to surveying the removal bottoms and undercuts after approval by the geotechnical consultant and prior to the placement of fill. Staking should be provided to verify undercut locations and depths.

6.2.4 Treatment of Removal Bottoms
At the completion of removals/over-excavation, the exposed removal bottom should be ripped to a minimum depth of eight (8) inches, moisture-conditioned to above optimum moisture content and compacted in-place to the project standards.

6.2.5 Fill Placement
After removals are completed and scarification and compaction of the removal bottom is performed, additional fill may be placed. Fill should be placed in eight-inch bulk maximum lifts, moisture conditioned to optimum moisture content or above, compacted and tested as grading/construction progresses until final grades are attained.

Page 685 of 2028 ends

Project Number 1-0568 Page 13
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.

6.2.6 Moisture Content
The moisture content of the upper in-situ soils varies, as shown in the boring logs presented in Appendix B. The majority of the upper several feet of onsite soils are dry to slightly moist and will require moisture conditioning prior to placement as compacted fill.

6.2.7 Mixing
Mixing of materials may be necessary to prevent layering of different soil types and/or different moisture contents. The mixing should be accomplished prior to and as part of compaction of each fill lift.

6.2.8 Import Soils
Imported soils, if necessary, should consist of clean, structural quality, low expansive, compactable materials similar to the on-site soils and should be free of trash, debris or other objectionable materials. The project Geotechnical Consultant should be notified not less than 72 hours in advance of the locations of any soils proposed for import. Import sources should be sampled, tested, and approved by the project Geotechnical Consultant at the source prior to the importation of the soils to the site. The project Civil Engineer should include these requirements on plans and specifications for the project.

6.2.9 Utility Trenches

6.2.9.1 Excavation
Utility trenches should be supported, either by laying back excavations or shoring, in accordance with applicable OSHA standards. The existing site soils are classified as Soil Type "B" per OSHA standards. Upon completion of the
recommended removals and recompaction, the artificial fill will be classified as Soil Type “B”. The Project Geotechnical

Page 686 of 2028 ends

Project Number 1-0568 Page 14
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.

Consulting should be consulted if geologic conditions vary from what is presented in this report.

6.2.9.2 Backfill
Utility trench backfill within the City of Fullerton backfill shall conform to the City Standard of utilizing Class II aggregate base compacted to at least 90 percent of maximum dry
density as determined by ASTM D-1557.

From a geotechnical perspective, private utility trenches may utilize onsite soils as backfill, based on approval by the governing agencies. Onsite soils will not be suitable for use as bedding material but will be suitable for use in backfill provided oversized materials are removed. No surcharge
loads should be imposed above excavations. This includes spoil piles, lumber, concrete trucks, or other construction materials and equipment. Drainage above excavations
should be directed away from the banks. Care should be
taken to avoid saturation of the soils. Compaction should be accomplished by mechanical means. Jetting of native soils will not be acceptable.

Under-slab trenches should also be compacted to project specifications. If select granular backfill (SE > 30) is used, compaction by flooding may be acceptable.

Page 687 of 2028 ends

Project Number 1-0568 Page 15
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.

6.2.10 Backcut Stability
Temporary backcuts, if required during unsuitable soil removals, should be made no steeper than 1:1 without review and approval of the geotechnical consultant. Flatter backcuts may be necessary where geologic conditions dictate and where minimum width dimensions are to be maintained.

Care should be taken during remedial grading operations in order to minimize risk of failure. Should failure occur, complete removal of the disturbed material will be required.

In consideration of the inherent instability created by temporary construction backcuts for removals, it is imperative that grading schedules are coordinated to minimize the unsupported exposure time of these excavations. Once started, these excavations and subsequent fill operations should be maintained to completion without intervening delays imposed by avoidable circumstances. In cases where five-day workweeks comprise a normal schedule, grading should be planned to avoid exposing at-grade or near-grade excavations through a non-work weekend. Where improvements may be affected by temporary instability, either on or offsite, further restrictions such as slot cutting, extending work days, implementing weekend schedules, and/or other requirements considered critical to serving specific circumstances may be imposed.

6.3 Storm Water Infiltration Systems
From a geotechnical perspective, allowing storm water to infiltrate the onsite soil in concentrated areas increases the potential for settlement, liquefaction, and water-related damage to structures/improvements, such as wet slabs or pumping subgrade, and should be avoided where possible. If infiltration systems

Page 688 of 2028 ends

Project Number 1-0568 Page 16
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.
are required on this site, care should be taken in designing systems that control the storm water as much as possible.

Preliminary infiltration testing was as part of Alta’s geotechnical investigation.

The resulting infiltration rates for P-1 and P-2 were 0.8 and 0.1-inches per hour, respectively. The results do not include a factor of safety.

The Project Geotechnical Consultant should review the final WQMP design prior to construction.

6.4 Boundary Conditions
Construction of retaining/screen walls along the site boundaries may require additional geotechnical recommendations concerning unsuitable soil removals and foundation design parameters. Boundary conditions for the project should be reviewed by the Project Geotechnical Consultant as the design progresses.

7.0 DESIGN CONSIDERATIONS

7.1 Structural Design
It is anticipated that multi-story wood-framed residential structures with slab ongrade and shallow foundations will be constructed. Upon the completion of rough grading, finish grade samples should be collected and tested in order to provide specific recommendations as they relate to the individual building pads.

These test results and corresponding design recommendations should be presented in a final rough grading report. Final slab and foundation design recommendations should be made based upon specific structure sitings, loading conditions, and as-graded soil conditions.

It is anticipated that the majority of onsite soils will possess “very low” to “low” expansion potential when tested in general accordance with ASTM Test Method D: 4829. For budgeting purposes, the following foundation design requirements for a range of potential expansion characteristics are presented.

Page 689 of 2028 ends

Project Number 1-0568 Page 17
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.

7.1.1 Foundation Design
Foundations may be preliminary designed based on the values presented in Table 7-1 below.

Table 7-1
Foundation Design Parameters*
Allowable Bearing 2000 lbs/ft2 (assuming a minimum embedment depth and width of 12 inches)
Lateral Bearing 250 lbs/ft2 at a depth of 12 inches plus 250 lbs/ft2 for each additional 12 inches of embedment to a maximum of 2000
lbs/ft2
.

Sliding Coefficient 0.30
Settlement Static Settlement – 0.5 inch in 40 feet
Dynamic Settlement – 0.5 inch in 40 feet
*These values may be increased as allowed by Code to resist transient loads such as wind or seismic. Building code and structural design considerations may govern depth and reinforcement requirements and should be evaluated.

7.1.1 Conventional Foundation Systems
Based on the onsite soils conditions and information supplied by the CBC 2022, conventional foundation systems may be designed in accordance with Tables 7-1 and 7-2.

Page 690 of 2028 ends

Project Number 1-0568 Page 18
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.

TABLE 7-2

CONVENTIONAL FOUNDATION DESIGN PARAMETERS
Expansion Potential Very Low to Low
Soil Category I
Design Plasticity Index 12
Minimum Footing
Embedment 12 inches*
*The minimum footing imbedments presented herein are based on expansion indexes. The structural engineer should determine minimum embedments based on the number of floors supported by the footings, the structural loading, and the requirements of the latest California Building Code.

Minimum Footing Width
12-inches-The structural engineer should determine the minimum footing width based on loading and the latest California Building Code.

Minimum Footing Reinforcement No. 4 rebar, one (1) on top, one (1) on bottom Minimum Slab Thickness 4 inches (actual)
Minimum Slab Reinforcement No. 3 rebar spaced 18 inches on center, each way Under-Slab Requirement See Section 7.2
Slab Subgrade Moisture Minimum of 110 percent of optimum moisture to a depth of 12 inches prior to placing concrete.

Footing Embedment Adjacent to
Swales and Slopes
If exterior footings adjacent to drainage swales are to exist within five (5) feet horizontally of the swale, the footing should be embedded sufficiently to assure embedment below the swale bottom is maintained. Footings adjacent to slopes should be embedded such that at least five- (5) feet is provided horizontally from edge of the footing to the face of the slope.

Garages
A grade beam reinforced continuously with the garage footings shall be constructed across the garage entrance, tying together the ends of the perimeter footings and between individual spread footings. This grade beam should be embedded at the same depth as the adjacent perimeter footings. A thickened slab, separated by a cold joint from the garage beam, should be provided at the garage entrance. Minimum dimensions of the thickened edge shall be six (6) inches deep. Footing depth, width and reinforcement should be the same as the structure. Slab thickness, reinforcement and under-slab treatment should be the same as the structure.

7.1.2 Post-Tensioned Slabs/Foundation Design Recommendations Post-tensioned slabs for the project may be designed utilizing the parameters presented in Tables 7-1 and 7-3. The parameters presented herein are based on methodology provided in the Design of PostTensioned Slabs-On-Ground, Third Edition, by the Post-Tensioning Institute, in accordance with the 2022 CBC.

Page 691 of 2028 ends

Project Number 1-0568 Page 19
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.

TABLE 7-3

POST-TENSION SLAB DESIGN PARAMETERS
Category Expansion Potential Minimum
Embedment*
Edge Lift Center Lift
Em (ft) Ym
(inch) Em (ft) Ym (inch)
I Very Low to Low 12 inches 5.4 0.61 9.0 0.26
Slab Subgrade Moisture
Category I Minimum 110% of optimum moisture to a depth of 12 inches prior to pouring concrete
Embedment*
The minimum footing embedments presented herein are based on expansion indexes. The structural engineer should determine minimum embedments based on the number of floors supported by the footings, the structural loading, and the requirements of the latest California Building Code. If mat slabs are utilized, alternate embedment depths can be provided.

Moisture Barrier
A moisture barrier should be provided in accordance with the recommendations presented in Section 7.2 The parameters presented herein are based on procedures presented in the Design of Post-Tensioned Slabs-OnGround, Third Edition. No corrections for vertical barriers at the edge of the slab, or for adjacent vegetation have been assumed. The design parameters are based on a Constant Suction Value of 3.9 pF.

7.2 Moisture Barrier
A moisture and vapor retarding system should be placed below the slabs-ongrade in portions of the structure considered to be moisture sensitive and should be capable of effectively preventing the migration of water and reducing the transmission of water vapor to acceptable levels. Historically, a 10-mil plastic membrane, such as Visqueen, placed between two to four inches of clean sand, has been used for this purpose. The use of this system or other systems can be considered, at the discretion of the designer, provided the system reduces the vapor transmission rates to acceptable levels.

Page 692 of 2028 ends

Project Number 1-0568 Page 20
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.

7.3 Seismic Design
The site classes were determined based on the referenced reports and published geologic maps in the area in general conformance with Chapter 20 of ASCE 7-16.

Based on the density of the underlying soils, a Site Class of C (shear wave velocity of 259 m/s) was selected. The seismic design parameters were calculated using a program based on the USGS website and ASCE 7-16 procedures. The resulting values are presented in Table 7-4.

TABLE 7-4 Seismic Ground Motion Values
2022 CBC and ASCE 7-16
Parameter Value
Site Class C
Site Latitude 33.8899
Site Longitude -117.8009
Spectral Response Acceleration Parameter, SS 1.845
Spectral Response Acceleration Parameter, S1 0.65
Site Coefficient, Fa 1.2
Site Coefficient, Fv 1.4
MCE Spectral Response Acceleration Parameter, SMS 2.215 MCE Spectral Response Acceleration Parameter, SM1 0.909 Design Spectral Response Acceleration Parameter, SDS 1.476 Design Spectral Response Acceleration Parameter, SD1 0.606 Peak Ground Acceleration, PGAM 0.95

Page 693 of 2028 ends

Project Number 1-0568 Page 21
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.

7.4 Block Walls
Block walls, if used, should be embedded a minimum of 2 feet below the lowest adjacent grade. Construction joints (not more than 20 feet apart) should be included in the block wall construction. Side yard walls should be structurally separated from the rear yard wall.

7.5 Footing Excavations
Soils from the footing excavations should not be placed in slab-on-grade areas unless properly compacted and tested. The excavations should be cleaned of all loose/sloughed materials and be neatly trimmed at the time of concrete placement.

7.6 Retaining Wall Design
Retaining walls should be founded on compacted fill and should be backfilled with granular soils that allow for drainage behind the wall. Foundations may be designed in accordance with the recommendations presented in Table 7-1, above. Unrestrained walls, free to rotate at least 0.001 radians, may be designed to resist lateral pressures imposed by a fluid with a unit weight determined in accordance with Table 7-5 below. The table also presents design parameters for restrained retaining walls. These parameters may be used to design retaining walls that may be considered as restrained due to the method of construction or location (corner sections of unrestrained retaining walls).

TABLE 7-5
Equivalent Fluid Pressures for 90% Compacted Fill
Backfill Active Pressure (psf/ft) At-Rest Pressure (psf/ft) Level 35 55

Page 694 of 2028 ends

Project Number 1-0568 Page 22
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.

Per the requirements of the CBC, the seismic force acting on the retaining walls with backfill exceeding 6-feet in height may be resolved utilizing the formula

19.5H2 lb/lineal ft (H=height of the wall). This force acts at approximately 0.6H above the base of the wall (inverted triangle). The seismic value can be converted as required by the retaining wall engineer. Retaining walls should be designed in general accordance with Section 1807A.2 of the 2022 CBC.  Restrained retaining walls should be designed for “at-rest” conditions, utilizing at-rest pressure.
 The design loads presented in the above table are to be applied on the retaining wall in a horizontal fashion and as such friction between wall and retained soils should not be allowed in the retaining wall analyses.  Additional allowances should be made in the retaining wall design to account for the influence of construction loads, temporary loads, and possible nearby structural footing loads.
 Select backfill should be granular, structural quality backfill with a Sand Equivalent of 20 or better and an ASCE Expansion Index of 20 or less. The backfill must encompass the full active wedge area. The upper one foot of backfill should be comprised of native on-site soils (see Plate A).  The wall design should include waterproofing (where appropriate) and backdrains or weep holes for relieving possible hydrostatic pressures. The backdrain should be comprised of a 4-inch perforated PVC pipe in a 1 ft. by 1 ft., ¾-inch gravel matrix, wrapped with a geofabric. The backdrain should be installed with a minimum gradient of 2 percent and should be outletted to an appropriate location.
 No backfill should be placed against concrete until minimum design strengths are achieved.

It should be noted that the allowable bearing and lateral bearing values presented in Table 7-1 are based on level conditions at the toe. Modified design parameters can be presented for retaining walls with sloping condition at the toe.

Other conditions should be evaluated on a case-by-case basis.

Page 695 of 2028 ends

RETAINING WALL BACKFILL DETAIL
NATIVE

BACKFILL
12 tN. MtN.
*OR AS MODIFIED

BY A SPECIFIC REPORT
DRAIN I.ATERALLY,

OR PROVIDE WEEP

HOLES AS REQUIRED

TO DMIN
PIPE: 4-INCH PERFORATED PVC, SCHEDULE 40, SDR35 OR APPROVED ALTERNATE MINIMUM 8 PERFORATIONS (1/4-IN. DIA.) PER LINEAL FT. IN BOTTOM HALF OF PIPE
ROCK: MINIMUM VOLUME OF 1 CU. FT. OF 3/4_IN. MAX. ROCK PER. LINEAL FOOT

OF PIPE, OR APPROVED ALTERNATE
FILTER FABRIC: MIRAFI 140 FILTER FABRIC OR APPROVED EQUIVALENT "64
ALTA cALTFoRNTA eEorEcl{NrcAL, tNc,
'vER, tTto PI-ATE A
PATH: S\Drofllns\ALTA GEoTECHNICAI\GRAoING DETAIIS\PLATE Page 696 of 2028 A.dws Project Number 1-0568 Page 23
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.

7.7 Exterior Slabs and Walkways
Exterior concrete slabs and walkways should be designed and constructed in consideration of the following recommendations.

7.7.1 Subgrade Compaction
The subgrade below exterior concrete slabs should be compacted to a minimum of 90 percent relative compaction as determined by ASTM Test Method: D 1557.

7.7.2 Subgrade Moisture
The subgrade below concrete slabs should be moisture conditioned to a minimum of 110 percent of optimum moisture prior to concrete placement.

7.7.3 Concrete Slab Thickness
Concrete flatwork and driveways should be designed utilizing four-inch minimum thickness.

7.7.4 Concrete Slab Reinforcement
Utilization of reinforcement for flatwork and driveways is subject to a cost/benefit analysis for the developer. Reinforcement will decrease the amount of cracking that may occur in flatwork, however, planning for occasional repairs may be more cost effective. Utilizing closely spaced control joints is likely more cost-effective than utilizing reinforcement.

The majority of the soils onsite are classified as medium to high in expansion potential. Consideration should be given to reinforcing flatwork with irregular (non-square/rectangular) shapes. Reinforcement may consist of 6x6 W.14/W1.4 welded wire mesh or an equivalent section of rebar.

Page 697 of 2028 ends

Project Number 1-0568 Page 24
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.

7.7.5 Control Joints
Weakened plane joints should be installed on walkways at intervals of approximately eight feet. Exterior slabs should be designed to withstand shrinkage of the concrete.

7.8 Concrete Design
As stated in Section 5.1.6, negligible concentrations of sulfates were detected in the onsite soils. Therefore, the use of sulfate resistant concrete is not required per ACI 318-14 at this time. Post-grading conditions should be evaluated, and final recommendations made at that time.

7.9 Corrosion
Based on preliminary testing from our investigation and the previous investigation, the onsite soils are classified as “non-corrosive” (Caltrans, 2022).

Consideration should be given to protecting buried metals from corrosion.

Typical measures may include using non-corrosive backfill, protective coatings, wrapping, plastic pipes, or a combination of these methods. A corrosion engineer should be consulted if specific design recommendations are required by the improvement designer.

Per ACI 318-14, an exposure class of C1 would be applicable to metals encased in concrete (rebar in footings) due to being exposed to moisture from surrounding soils. Per Table 19.3.2.1 of ACI 318-14, the requirements for concrete with an exposure class of C1 are a minimum compressive strength of 2500 psi and a maximum water-soluble chloride ion content in concrete of 0.30 (percent by weight of cement).

Page 698 of 2028 ends

Project Number 1-0568 Page 25
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.

7.10 Pavement Design
Pavement sections for the proposed streets shall be designed based on laboratory testing conducted on samples taken from the soil subgrade.

Preliminarily, based on an assumed R-Value of 30, the pavement may be designed utilizing the sections presented in Table 7-6. These sections should be verified upon the completion of grading, based on R-Value testing. The ultimate pavement section design for public streets is under the City of Yorba Linda’s purview.

Table 7-6
Preliminary Pavement Sections
Traffic
Index
Pavement Section Options
OR

5.0 3-inch AC on 6-inch AB 4-inch AC on 4-inch AB

5.5 3-inch AC on 7-inch AB 4-inch AC on 5-inch AB

6.0 3.5-inch AC on 7.5-inch AB 4.5-inch AC on 6.5-inch AB AC-Asphalt Concrete
AB-Caltrans Class II Base
Construction of the streets should be accomplished in accordance with the current criteria of the City of Yorba Linda. Prior to the placement of base material, the subgrade should be suitably moisture conditioned, processed and compacted to a minimum 95 percent of the laboratory maximum density (ASTM:

D 1557) to at least twelve (12) inches below subgrade. After subgrade compaction, the exposed grade should then be "proof"-rolled with heavy equipment to ensure the grade does not "pump" and is verified as non-yielding.

Aggregate base material should be placed on the compacted subgrade and compacted in-place to a minimum 95 percent of the laboratory standard obtained per ASTM: D 1557.

Page 699 of 2028 ends

Project Number 1-0568 Page 26
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.

7.11 Site Drainage
Positive drainage away from the proposed structures should be provided and maintained. Roof, pad, and lot drainage should be collected and directed away from the structures toward approved disposal areas through drainage terraces, gutters, down drains, and other devices. Design fine grade elevations should be maintained through the life of the structure or if design fine grade elevations are altered, adequate area drains should be installed in order to provide rapid discharge of water, away from structures.

8.0 LOT MAINTENANCE
Ongoing maintenance of the improvements is essential to the long-term performance of structures and slopes. As such, the owners must implement certain maintenance procedures. The attached "Maintenance and Improvement Considerations" presented in Appendix D should be reviewed for issues related to drainage, slopes, maintenance, backyard improvements, etc. The following recommendations should also be implemented.

8.1 Lot Drainage
Roof, pad and lot drainage should be collected and directed away from structures and slopes and toward approved disposal areas. Design fine grade elevations should be maintained throughout the life of the structure or if design fine grade elevations are altered, adequate area drains should be installed in order to provide rapid discharge of water, away from structures and slopes.

Residents should be made aware that they are responsible for maintenance and cleaning of all drainage terraces, down drains, and other devices that have been installed to promote structure and slope stability.

Page 700 of 2028 ends

Project Number 1-0568 Page 27
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.

8.2 Burrowing Animals
Residents or owners should undertake a program for the elimination of burrowing animals. This should be an ongoing program in order to maintain slope stability.

9.0 FUTURE PLAN REVIEWS
This report represents a geotechnical review of the tract map. As the project design progresses, site specific geologic and geotechnical issues need to be considered in the design and construction of the project. Consequently, future plan reviews may be necessary. These reviews may include reviews of:
 Grading Plans
 Foundation plans
 Utility Plans
These plans should be forwarded to the Project Geotechnical Consultant for review.

10.0 CLOSURE

10.1 Geotechnical Review
For the purposes of this report, multiple working hypotheses were established for the project, utilizing the available data and the most probable model is used for the analysis. Future information collected during the proposed grading operations is intended to evaluate the hypothesis and as such, some of the assumptions summarized in this report may need to be changed. Some modifications of the grading recommendations may become necessary, should the conditions encountered in the field differ from the conditions hypothesized in this report.

Plans and sections of the project specifications should be reviewed by Alta, to evaluate conformance with the intent of the recommendations contained in this report. If the project description or final design varies from that described in

Page 701 of 2028 ends

Project Number 1-0568 Page 28
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.
herein, Alta must be consulted regarding the applicability of the recommendations contained herein and whether any changes are required. Alta accepts no liability for any use of its recommendations if the project description or final design varies and Alta is not consulted regarding the alterations.

10.2 Limitations
This report is based on the following: 1) the project as presented on the attached plan; 2) the information obtained from the subsurface investigation at the approximate locations indicated on the plans included herein; and 3) from the information presented in the referenced reports. The findings and recommendations are based on the results of the subsurface investigation, laboratory testing, and office analysis combined with an interpolation and extrapolation of conditions between and beyond the subsurface excavation locations. However, the materials adjacent to or beneath those observed may have different characteristics than those observed, and no precise representations are made as to the quality or extent of the materials not observed. The results reflect an interpretation of the direct evidence obtained.

Work performed by Alta has been conducted in a manner consistent with the level of care and skill ordinarily exercised by members of the geotechnical profession currently practicing in the same locality under similar conditions. No other representation, either expressed or implied, and no warranty or guarantee is included or intended.

The recommendations presented in this report are based on the assumption that an appropriate level of field review will be provided by a geotechnical consultant who is familiar with the design and site geologic conditions. That field review shall be sufficient to confirm that geotechnical and geologic conditions exposed during grading are consistent with the geologic representations and corresponding recommendations presented in this report.

Page 702 of 2028 ends

Project Number 1-0568 Page 29
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.

The conclusions and recommendations included in this report are applicable to the specific design of this project as discussed in this report. They have no applicability to any other project or to any other location and any and all subsequent users accept any and all liability resulting from any use or reuse of the data, opinions, and recommendations without the prior written consent of Alta.

Alta has no responsibility for construction means, methods, techniques, sequences, procedures, safety precautions, programs in connection with the construction, acts or omissions of the CONTRACTOR or any other person performing any of the construction, or for the failure of any of them to carry out the construction in accordance with the final design drawings and specifications

Page 703 of 2028 ends

ALTA CALIFORNIA GEOTECHNICAL, INC.

APPENDIX A

REFERENCES

Page 704 of 2028 ends

Project Number 1-0568 Page A-1
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.

APPENDIX A
Selected References
California Code of Regulations, 2022, California Building Code, Title 24, Part 2, Volume 2, Based on the 2021 International Building Code, Effective Date January 1, 2023.

California Department of Water Resources, Water Data Library, 2022, Website, http://www.wdl.water.ca.gove/waterdatalibrary/
California Division of Mines and Geology, 2008, Guidelines for evaluating and mitigating seismic hazards in California: Department of Conservation, Special Publication 117a.

California Geological Survey, 1999, Earthquake Fault Zones, A Guide for Government Agencies, Property Owners/Developers, And Geoscience Practitioners for Assessing Fault Rupture Hazards in California, Special Publication 42, Revised 1999.

California State Water Resources Control Board, Geotracker, 2024, Website, https://geotracker.waterboards.ca.gov/
Dibble, 2001, Geologic Map of the Whittier and La Habra quadrangles, Western Puente Hills, Los Angeles and Orange Counties, California.

Historical Aerials.com, 2024, online vertical and color aerials photographs from 1946 through 2022, viewed January 2025, http://www.historicaerials.com/ Jennings, C.W., and Bryant, W.A., 2010, Fault Activity Map of California: California Geological Survey Geologic Data Map No. 6, map scale 1:750,000.

Jennings, C. W., and Bryant, W. A., 2021, An explanatory test to accompany the Fault Activity Map of California: California Department of Conservation, California Geological Survey.

Jennings, C. W., 1985, An explanatory text to accompany the 1:750,000 scale fault and geologic map of California: California Division of Mines and Geology, Bulletin 201, 197p.

Romanoff, Melvin, 1989, Underground Corrosion, NBS Circular 579, Reprinted by NACE, Houston, TX, 1989.

U.S. Geological Survey, 2008, National Seismic Hazards Maps – Source Parameters, http://geohazards.usgs.gov/cfusion/hazfaults_2008_search/query_main.cfm.

Page 705 of 2028 ends

ALTA CALIFORNIA GEOTECHNICAL, INC.

APPENDIX B
Subsurface Investigation

Page 706 of 2028 ends

Project No. 1-0568 Page B-1
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.

APPENDIX B
Subsurface Investigation
Alta's subsurface investigation consisted of excavating, logging, and sampling five (5) hollowstem auger borings. In addition, two shallow borings were advanced for preliminary infiltration testing. Details of the subsurface investigation are presented in Table B-1. The approximate locations of the exploratory excavations are shown on the accompanying Plate 1 and the Geotechnical Logs are attached.

TABLE B-1

SURFACE INVESTIGATION DETAILS
Equipment Range of
Depths
Sampling Methods Sample Locations
8” HollowStem Auger Up to 51.0
feet

1. Bulk Samples

2. Ring Samples

1. Bulk-Select Depths

2. Ring-Every 2.5 or 5.0 feet.

Page 707 of 2028 ends

UNIFIED SOI L CLASSIFIICATION SYSTEM
Major Divisions lfl tr Description Major Divisions an tr Coarse
Grained
Soils
N4ore than
50%
retained on
No 200
steve
Gravel
and
Sravelly
Soils
han 50%
frachon
relained
on No, 4
'l
ts
*
,-l*
EIF
GW
Well-graded grcvels or gravel sand
mixtures, little or no fines
Fine
(lrained
isoils
l\lore than
Silts
And
Clays
LL,<50
n
ML
Inorganic silts and very fine sands,
rock flour, silty or clayey fine sands
or clavev silts with slioht olasticitv
GP
Poorly-graded gravels or gravel
sand mixture, little or no fines CL
Inorganic clays of low to medium
plasticity, gravelly clays, sandy
clays, silty clays, lean clays Silty gravels, gravel-sand-silt mixtures
OL
Organic silts and organic silt-clays
of low plasticity
Clayey gravels, gravel-sand-clay
mixtures
Silts
And
Clays
LL,<50
MF
Inorganic silts, micaceous or
diatomaceous fine or silty soils,
elastic silts Sand
and
Sandy
Soils
than 50%
fraclion
Passes
on No, 4
i'+.
3_'. JV!
Well-graded sands or gravelly
sands, little or no fines
on No 200
steve VH
Inorganic clays of high plasticity,
fat clays SP
Poorly-graded sands or gravelly
sands, little or no fines
SM Silty sands, sarrd-silt mixtures OF
Organic clays of medium to high
plasticity
sc Clayey sands, and-clay mixtures Highly Organic
Soils PT Peat and other highly organic soils
BoUNDARY CLASSIFICATIoN: Soils possessing characteristics of two groups are designated by combinations of group symbols PARTICLE SIZ:E LIMITS
U.S. STANDA,RD SiERIES SIEVE
200 40 10 4

CLEAR SQUARE SIEVE OPENINGS
3t4" 3,, ,t2"

LABORATORY TESTS
Symbol Tesl
DS
DSR
cc)N
SA
MAX
RV
EI
SE
AL
CHEM
HY
Direct Shear
Direct Shear
(Remolded)
Sieve Analysis
Maximum Density
Resistance (R) Value
Expansion Index
Sand Equivalent
Atterberg Limits
Chemical Analysis
Hydrometer Analysis

SOIL MOISTURE

SIZE PROPORTIONS
Trace - <5%
Few-5to10%
Some - 15 to 25%
Increasing \/isual Moisture Content
Silts
an0
Clays
Sand Gravel
Cobbles Boulders
Fine Medium Coarsi€r Fine Coarse

RELATIVE DENSITY
Sands and Gravels Blows/Foot (SPT)
Very Loose
Loose
Medium Dense
Dense
Very Dense
<4
4-10
11-30
31 -50
>50

CON SI STENCY C IASSI FI CATI ON
Silts and Clays Criteria
Very Soft
Soft
Firm
stiff
Very Stiff
Thumb penetrates soil >1 in.

Thumb penetrates soil 1 in,
Thumb penetrates soil 1/4 in
Readily indented with thumbnail
Thumbnail will not indent soil

HARDNESS
KEY TO EXPLORATORY BORING LOGS}
,n
/L>//J, ALTA CALIFORNTA GEOTECHNTCAL tNC.
/\ Page 708 of 2028 PI-ATE B

Page 709 of 2028 ends

Page 710 of 2028 ends

Page 711 of 2028 ends

Page 712 of 2028 ends

Page 713 of 2028 ends

Page 714 of 2028 ends

Page 715 of 2028 ends

Page 716 of 2028 ends

Page 717 of 2028 ends

ALTA CALIFORNIA GEOTECHNICAL, INC.

APPENDIX C
Laboratory Testing

Page 718 of 2028 ends

Project No. 1-0568 Page C-1
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.

LABORATORY TESTING
The following laboratory tests were performed on representative samples in accordance with the applicable latest standards or methods from the ASTM, California Building Code (CBC) and California Department of Transportation.

Classification
Soils were classified with respect to the Unified Soil Classification System (USCS) in accordance with ASTM D-2487 and D-2488.

Particle Size Analysis
Modified hydrometer testing was conducted to aid in classification of the soil. The results of the particle size analysis are presented in Table 7-1 and Table C.

Maximum Density/Optimum Moisture
The maximum dry density and optimum moisture content of one (1) representative bulk sample was evaluated in accordance with ASTM D-1557. The results are summarized in Table C.

Expansion Index Tests
One (1) expansion index test was performed to evaluate the expansion potential of typical onsite soil. Testing was carried out in general conformance with ASTM Test Method D-4829. The results are presented in Table C.

Consolidation Tests
Consolidation testing was performed on two (2) relatively “undisturbed” soil sample at their natural moisture content in accordance with procedures outlined in ASTM D-2435. The samples were placed in a consolidometer and loads were applied incrementally in geometric progression. The samples (2.42-inches in diameter and 1-inch in height) were permitted to consolidate under each load increment until the slope of the characteristic linear secondary compression portion of the thickness versus log of time plot was apparent. The percent consolidation for each load cycle was recorded as the ratio of the amount of vertical

Page 719 of 2028 ends

Project Number 1-0568 Page C-2
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.
compression to the original 1-inch height. The consolidation test results are shown on Plate C1.

Chemical Analyses
Chemical testing was performed on one select sample. The results of this test (sulfate content, resistivity, chloride content and pH) is presented on Table C.

Page 720 of 2028 ends

Page 721 of 2028 ends

Page 722 of 2028 ends

Page 723 of 2028 ends

ALTA CALIFORNIA GEOTECHNICAL, INC.

APPENDIX D
Maintenance and Improvement Considerations

Page 724 of 2028 ends

Project Number 1-0568 Page D-1
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.

MAINTENANCE AND IMPROVEMENT CONSIDERATIONS
General
Owners purchasing property must assume a certain degree of responsibility for improvements and for maintaining conditions around their home. Of primary importance from a geotechnical standpoint are maintaining drainage patterns and minimizing the soil moisture variation below all improvements. Such design, construction and owner maintenance provisions may include:
 Employing contractors for improvements who design and build in recognition of local building codes and specific site soils conditions.
 Establishing and maintaining positive drainage away from all foundations, walkways, driveways, patios, and other improvements.
 Avoiding the construction of planters adjacent to structural improvements.

Alternatively, planter sides/bottoms can be sealed with an impermeable membrane and drained away from the improvements via subdrains into approved disposal areas.  Sealing and maintaining construction/control joints within concrete slabs and walkways to reduce the potential for moisture infiltration into the subgrade soils.  Utilizing landscaping schemes with vegetation that requires minimal watering. Watering should be done in a uniform manner, as equally as possible on all sides of the foundation, keeping the soil "moist" but not allowing the soil to become saturated.  Maintaining positive drainage away from structures and providing roof gutters on all structures with downspouts that are designed to carry roof runoff directly into area drains or discharged well away from the foundation areas.  Avoiding the placement of trees closer to the proposed structures than a distance of one-half the mature height of the tree.
 Observation of the soil conditions around the perimeter of the structure during extremely hot/dry or unusually wet weather conditions so that modifications can be made in irrigation programs to maintain relatively uniform moisture conditions.

Sulfates
Owners should be cautioned against the import and use of certain inorganic fertilizers, soil amendments, and/or other soils from offsite sources in the absence of specific information relating to their chemical composition. Some fertilizers have been known to leach sulfate compounds into soils and increase the sulfate concentrations to potentially detrimental levels.

Page 725 of 2028 ends

Project Number 1-0568 Page D-2
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.

Site Drainage
 The owners should be made aware of the potential problems that may develop when drainage is altered through construction of hardscape improvements. Ponded water, drainage over the slope face, leaking irrigation systems, overwatering, or other conditions which could lead to ground saturation must be avoided.  No water should be allowed to flow over the slopes. No alteration of pad gradients should be allowed that would prevent pad and roof runoff from being directed to approved disposal areas.
 Drainage patterns have been established at the time of the fine grading should be maintained throughout the life of the structure. No alterations to these drainage patterns should be made unless designed by qualified professionals in compliance with local code requirements and site-specific soils conditions.

Slope Drainage
 Residents should be made aware of the importance of maintaining and cleaning all interceptor ditches, drainage terraces, down drains, and any other drainage devices, which have been installed to promote slope stability.
 Subsurface drainage pipe outlets may protrude through slope surfaces and/or wall faces. These pipes, in conjunction with the graded features, are essential to slope and wall stability and must be protected in-place. They should not be altered or damaged in any way.

Planting and Irrigation of Slopes
 Seeding and planting of the slopes should be planned to achieve, as rapidly as possible, a well-established and deep-rooted vegetal cover requiring minimal watering.  It is the responsibility of the landscape architect to provide such plants initially and of the residents to maintain such planting. Alteration of such a planting scheme is at the resident's risk.
 The resident is responsible for proper irrigation and for maintenance and repair of properly installed irrigation systems. Leaks should be fixed immediately.  Sprinklers should be adjusted to provide maximum uniform coverage with a minimum of water usage and overlap. Overwatering with consequent wasteful runoff and serious ground saturation must be avoided.
 If automatic sprinkler systems are installed, their use must be adjusted to account for seasonal and natural rainfall conditions.

Page 726 of 2028 ends

Project Number 1-0568 Page D-3
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.

Burrowing Animals
 Residents must undertake a program to eliminate burrowing animals. This must be an ongoing program in order to promote slope stability.

Owner Improvement
Owner improvements (pools, spas, patio slabs, retaining walls, planters, etc.) should be designed to account for the terrain of the project, as well as expansive soil conditions and chemical characteristics. Design considerations on any given lot may need to include provisions for differential bearing materials, ascending/descending slope conditions, bedrock structure, perched (irrigation) water, special geologic surcharge loading conditions, expansive soil stresses, and long-term creep/settlement.

All owner improvements should be designed and constructed by qualified professionals utilizing appropriate design methodologies, which account for the on-site soils and geologic conditions.

Each lot and proposed improvement should be evaluated on an individual basis.

Setback Zones
Manufactured slopes may be subject to long-term settlement and creep that can manifest itself in the form of both horizontal and vertical movement. These movements typically are produced as a result of weathering, erosion, gravity forces, and other natural phenomenon. A setback adjacent to slopes is required by most building codes, including the California Building Code. This zone is intended to locate and support the residential structures away from these slopes and onto soils that are not subject to the potential adverse effects of these natural phenomena.

The owner may wish to construct patios, walls, walkways, planters, swimming pools, spas, etc. within this zone. Such facilities may be sensitive to settlement and creep and should not be constructed within the setback zone unless properly engineered. It is suggested that plans for such improvements be designed by a professional engineer who is familiar with grading ordinances and design and construction requirements. In addition, we recommend that the

Page 727 of 2028 ends

Project Number 1-0568 Page D-4
DRAFT
ALTA CALIFORNIA GEOTECHNICAL, INC.
designer and contractor familiarize themselves with the site specific geologic and geotechnical conditions on the specific lot.

Page 728 of 2028 ends

ALTA CALIFORNIA GEOTECHNICAL, INC.

APPENDIX E
Earthwork Specifications

Page 729 of 2028 ends

Page 730 of 2028 ends

Page 731 of 2028 ends

Page 732 of 2028 ends

Page 733 of 2028 ends

Page 734 of 2028 ends

Legend
Approximate Location of Hollow Stem Auger Boring
Approximate Location of Infiltration Test
200 ft
N
➤

Page 735 of 2028 ends

Phase I Environmental Site
Assessment
19081 Yorba Linda Boulevard
Yorba Linda, California 92886
April 20, 2022
Prepared for:

City Ventures
3121 Michelson Drive, Suite 150
Irvine, California 92612
Prepared by:

Stantec Consulting Services Inc.
735 East Carnegie Drive, Suite 280
San Bernardino, California 92408
Project No.: 185805577

Page 736 of 2028 ends

Sign-off Sheet and Signatures of Environmental Professionals Project No.: 185805577
This document entitled Phase I Environment Site Assessment was prepared by Stantec Consulting Services Inc. (“Stantec”) for the account of City Ventures (the “Client”). Any reliance on this document by any third party is strictly prohibited. Any use which a third party makes of this document is the responsibility of such third party. Such third party agrees that Stantec shall not be responsible for costs or damages of any kind, if any, suffered by it or any other third party as a result of decisions made or actions taken based on this document.

All information, conclusions, and recommendations provided by Stantec in this document regarding the Phase I ESA have been prepared under the supervision of and reviewed by the professionals whose signatures appear below.

Author:

Jennifer Alvarado
Project Scientist
I declare that, to the best of my professional knowledge and belief, I meet the definition of Environmental Professional as defined in § 312.10 of Title 40 of the Code of Federal Regulations, Part 312, (40 CFR 312). I have the specific qualifications based on education, training, and experience to assess a property of the nature, history, and setting of the property. I have developed and performed all the appropriate inquiries in conformance with the standards and practices set forth in 40 CFR Part 312.

Quality Reviewer:

Alicia Jansen
Senior Scientist
Independent Reviewer:

Kyle Emerson, C.E.G., P.G.

Managing Principal Geologist

Page 737 of 2028 ends

19081 YORBA LINDA BOULEVARD
YORBA LINDA, CALIFORNIA 92886
Project No.: 185805577 i
Table of Contents
ABBREVIATIONS ......................................................................................................................... III

1.0 EXECUTIVE SUMMARY................................................................................................. 1.1

2.0 INTRODUCTION ............................................................................................................. 2.1

2.1 SUBJECT PROPERTY DESCRIPTION.......................................................................... 2.2

2.2 SPECIAL TERMS, CONDITIONS, AND ADDITIONAL ASSUMPTIONS....................... 2.2

2.3 EXCEPTIONS AND LIMITING CONDITIONS ................................................................ 2.3

2.4 PERSONNEL QUALIFICATIONS ................................................................................... 2.3

3.0 USER-PROVIDED INFORMATION................................................................................ 3.1

4.0 RECORDS REVIEW........................................................................................................ 4.1

4.1 PHYSICAL SETTING ...................................................................................................... 4.1

4.1.1 Subject Property Topography and Surface Water Flow ............................... 4.1

4.1.2 Regional and Subject Property Geology ....................................................... 4.2

4.1.3 Regional and Subject Property Hydrogeology .............................................. 4.2

4.2 FEDERAL, STATE AND TRIBAL ENVIRONMENTAL RECORDS................................ 4.2

4.2.1 Listings for Subject Property.......................................................................... 4.3

4.2.2 Listings for Adjoining and Nearby Sites with Potential to Impact Subject Property ............................................................................................ 4.3

4.3 LOCAL/REGIONAL ENVIRONMENTAL RECORDS...................................................... 4.4

4.3.1 Local Health Department............................................................................... 4.5

4.3.1 California Geologic Energy Management Division (CalGEM) ...................... 4.6

4.3.2 Fire Department............................................................................................. 4.6

4.3.3 Local Building and/or Planning Department Records ................................... 4.6

4.3.4 Local/Regional Pollution Control Agency Department Records ................... 4.7

4.3.5 Local/Regional Water Quality Agency Records ............................................ 4.7

4.4 HISTORICAL RECORDS REVIEW................................................................................. 4.8

4.4.1 Land Title Records/Deeds ............................................................................. 4.8

4.4.2 Aerial Photographs ........................................................................................ 4.8

4.4.3 City Directories............................................................................................... 4.8

4.4.4 Historical Fire Insurance Maps...................................................................... 4.9

4.4.5 Historical Topographic Maps ......................................................................... 4.9

4.4.6 Other Historical Sources.............................................................................. 4.10

5.0 SITE RECONNAISSANCE.............................................................................................. 5.1

5.1 SITE RECONNAISSANCE METHODOLOGY................................................................ 5.1

5.2 GENERAL DESCRIPTION.............................................................................................. 5.1

5.3 HAZARDOUS SUBSTANCES AND PETROLEUM PRODUCTS .................................. 5.2

5.4 INTERIOR OBSERVATIONS.......................................................................................... 5.2

5.5 EXTERIOR OBSERVATIONS......................................................................................... 5.3

5.6 UNDERGROUND STORAGE TANKS/STRUCTURES.................................................. 5.3

5.7 ABOVEGROUND STORAGE TANKS ............................................................................ 5.3

5.8 ADJOINING PROPERTIES............................................................................................. 5.4

5.8.1 Current Uses of Adjoining Properties............................................................ 5.4

Page 738 of 2028 ends

19081 YORBA LINDA BOULEVARD
YORBA LINDA, CALIFORNIA 92886
Project No.: 185805577 ii

5.8.2 Observed Evidence of Past Uses of Adjoining Properties............................ 5.4

5.8.3 Pits, Ponds or Lagoons on Adjoining Properties........................................... 5.4

5.9 OBSERVED PHYSICAL SETTING................................................................................. 5.4

6.0 INTERVIEWS................................................................................................................... 6.1

7.0 EVALUATION.................................................................................................................. 7.1

7.1 FINDINGS AND OPINIONS ............................................................................................ 7.1

7.2 DATA GAPS..................................................................................................................... 7.1

7.3 CONCLUSIONS............................................................................................................... 7.2

8.0 NON-SCOPE CONSIDERATIONS................................................................................. 8.1

8.1 LEAD-BASED PAINT ...................................................................................................... 8.1

8.2 ASBESTOS...................................................................................................................... 8.1

8.3 RADON ............................................................................................................................ 8.1

8.4 FLOOD ZONES ............................................................................................................... 8.2

9.0 REFERENCES ................................................................................................................ 9.3

LIST OF FIGURES
FIGURE 1 Subject Property and Vicinity Map
FIGURE 2 Subject Property Map

LIST OF APPENDICES
APPENDIX A PHOTOGRAPHS OF THE PROPERTY AND VICINITY..............................A.1 APPENDIX B STANTEC RESUMES...................................................................................B.1 APPENDIX C USER PROVIDED RECORDS......................................................................C.1 APPENDIX D ENVIRONMENTAL AGENCY DATABASE SEARCH REPORT.................D.1 APPENDIX E HISTORICAL RECORDS..............................................................................E.1 APPENDIX F AGENCY RECORDS ....................................................................................F.1 APPENDIX G INTERVIEW FORMS.................................................................................... G.1

Page 739 of 2028 ends

19081 YORBA LINDA BOULEVARD
YORBA LINDA, CALIFORNIA 92886
Project No.: 185805577 iii
Abbreviations
AAI All Appropriate Inquiries
ACM Asbestos-containing material
AST Aboveground Storage Tank
ASTM ASTM International
AUL Activity Use Limitation
BER Business Environmental Risk
CERCLA Comprehensive Environmental Response, Compensation, and Liability Act CFR Code of Federal Regulation
CREC Controlled Recognized Environmental Conditions
DTSC Department of Toxic Substances Control
EP Environmental Professional
EPA Environmental Protection Agency
ESA Environmental Site Assessment
ft msl Feet above mean sea level
HREC Historical Recognized Environmental Conditions
LBP Lead-based paint
LUST Leaking Underground Storage Tank
NESHAP National Emissions Standard for Hazardous Air Pollutants PCBs Polychlorinated Biphenyls
RCRA Resource Conservation and Recovery Act
REC Recognized Environmental Conditions
USDA United States Department of Agriculture
USGS United States Geological Survey
UST Underground Storage Tank
VEC Vapor Encroachment Condition
VOCs Volatile Organic Compounds

Page 740 of 2028 ends

19081 YORBA LINDA BOULEVARD
YORBA LINDA, CALIFORNIA 92886
ExecutIve Summary
Project No.: 185805577 1.1

1.0 EXECUTIVE SUMMARY
Stantec Consulting Services Inc. (Stantec) has completed a Phase I Environmental Site Assessment (ESA) report of the property located at 19081 Yorba Linda Boulevard, within the City of Yorba Linda, California (the “Subject Property”), on behalf of City Ventures (the “Client”). The work was performed according to the Master Services Agreement between Stantec and the Client (the “MSA”). In the event of any conflict between the terms and conditions of this report and the terms and conditions of the MSA, the MSA shall control. City Ventures (the “User”) has been designated as the User of this report. The intended use of this Phase I ESA is for due diligence in support of acquisition for redevelopment.

The Phase I ESA was conducted in conformance with the requirements of ASTM International (ASTM) Designation E1527-21 and E1527-13, and All Appropriate Inquiries (AAI) as defined by the United States Environmental Protection Agency (EPA) in Title 40 of the Code of Federal Regulations, Part 312 (40 CFR 312), except as may have been modified by the scope of work, and terms and conditions, requested by the Client. Any exceptions to, or deletions from, the ASTM or AAI practice are described in Section 2.3.

The Subject Property consists of approximately 2.74 acres of land developed with a small orchard with orange, avocado, and dragonfruit and three residential structures and support buildings (i.e. garage and storage sheds). Adjoining properties, as well as the nearby area, generally include residential properties and a park. A Subject Property Location Map is provided as Figure 1. A Subject Property Vicinity Map illustrating the main features of the Subject Property and vicinity is provided as Figure 2. Photographs taken during the site reconnaissance visit are provided in Appendix A.

According to records obtained through Environmental Data Resources (EDR), the Subject Property has been agriculturally developed since at least the 1930s, and partially residentially developed since the 1960s.

Additionally, one 500-gallon gasoline underground storage tank (UST) was removed on April 27, 2020. Soil samples were collected from 5-feet below ground surface (bgs) on both ends of the tank excavation and showed only minor detections of gasoline (0.27 milligrams per kilogram (mg/kg)), xylenes (0.0091 mg/kg), and toluene (0.012 mg/kg), however, no soil vapor samples were collected. Based on this data, the Orange County Health Care Agency provided a case closure letter dated June 2, 2020 for the former UST.

We have performed a Phase I ESA in conformance with the scope and limitations of ASTM Practice E1527-21 and E1527-13 of the Subject Property. Any exceptions to, or deletions from, this practice are described in Section 2.3 of this report. This assessment has revealed the following evidence of recognized environmental conditions (RECs) with the Subject Property:
• Former UST. The Subject Property formerly contained a 500-gallon gasoline UST, multiple hazardous waste containers, and contaminated soil that were removed in 2020. Shallow soil sampling was also performed at this time; contaminants were not reported above residential screening levels. However, soil vapor sampling was not conducted at the Subject Property. This represents a potential vapor encroachment condition (VEC) and is considered a REC for the Subject Property. It is recommended that a Phase II subsurface investigation be conducted to evaluate soil vapor conditions in the vicinity of the features highlighted above.

Page 741 of 2028 ends

19081 YORBA LINDA BOULEVARD
YORBA LINDA, CALIFORNIA 92886
ExecutIve Summary
Project No.: 185805577 1.2
• Historical Agricultural Use. The majority of the Subject Property is utilized as an orange, avocado, and dragon fruit orchard; and the Subject Property has been agricultural in use since at least the 1930s. Application of pesticides and herbicides is considered likely to have occurred during this time period, potentially resulting in the accumulation of pesticides and metals (lead and arsenic) commonly associated with herbicide application in shallow soils at the Subject Property. Therefore, the former and current agricultural activity on the Subject Property is considered a REC. Stantec recommends performing a shallow soil investigation on the Subject Property to sample and analyze soil for the presence of pesticides and the heavy metals that typically accompany herbicide application (i.e., arsenic and lead).

The preceding summary is intended for informational purposes only. Reading of the full body of this report is recommended.

Page 742 of 2028 ends

19081 YORBA LINDA BOULEVARD
YORBA LINDA, CALIFORNIA 92886
Introduction
Project No.: 185805577 2.1

2.0 INTRODUCTION
The objective of this Phase I ESA was to perform All Appropriate Inquiries (AAI) into the past ownership and uses of the Subject Property consistent with good commercial or customary practice as outlined by ASTM International (ASTM) in “Standard Practice for Environmental Site Assessments: Phase I Environmental Site Assessment Process”, Designation E1527-21 and E1527-13. “All Appropriate Inquiries” (AAI) is the process for evaluating a property’s environmental conditions for the purpose of qualifying for landowner liability protections under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). following final rule of Part 312 of Title 40, Code of Federal Regulations (40 CFR Part 312). The purpose of this Phase I ESA was to identify, to the extent feasible, adverse environmental conditions including recognized environmental conditions (“RECs”) of the Subject Property. While the AAI Rule still references the ASTM E1527-13 standard until fully accepted by the United States Environmental Protection Agency (USEPA), this report incorporates procedures as prescribed in ASTM E1527-21, which is the current published ASTM standard for Phase I ESAs.

The ASTM E1527-21 standard indicates that the goal of the Phase I ESA is to identify RECs, including historical recognized environmental conditions (“HRECs”), and controlled recognized environmental conditions (“CRECs”) that may exist at a property. The term “recognized environmental conditions” means the presence or likely presence of any hazardous substances or petroleum products in, on, or at a property:
1) the presence of hazardous substances or petroleum products in, on, or at the Subject Property due to a release to the environment;
2) the likely presence of hazardous substances or petroleum products in, on, or at the Subject Property due to a release or likely release to the environment; or 3) the presence of hazardous substances or petroleum products in, on, or at the Subject Property under conditions that pose a material threat of a future release to the environment.

ASTM defines a “HREC” as a previous release of hazardous substances or petroleum products affecting the Subject property that has been addressed to the satisfaction of the applicable regulatory authority and meets current unrestricted use criteria established by a regulatory authority, without subjecting the property to any controls (e.g., activity and use limitations or other property use limitations). An HREC is not a REC.

ASTM defines a “CREC” as a REC resulting from a past release of hazardous substances or petroleum products that has been addressed to the satisfaction of the applicable regulatory authority (e.g., as evidenced by the issuance of a no further action letter or equivalent, or meeting risk-based criteria established by regulatory authority), but with hazardous substances or petroleum products allowed to remain in place subject to the implementation of required controls (e.g., property use restrictions, activity and use limitations, institutional controls, or engineering controls).

As defined by ASTM, RECs can include hazardous substances or petroleum products present under conditions in compliance with laws if that presence represents a material threat of future release. The release of hazardous substances or petroleum products is, however, not a REC if that presence is a de

Page 743 of 2028 ends

19081 YORBA LINDA BOULEVARD
YORBA LINDA, CALIFORNIA 92886
Introduction
Project No.: 185805577 2.2
minimis condition. De minimis conditions are minor releases that generally do not present a material risk to human health and would not likely be subject to enforcement action if brought to the attention of governmental agencies. ASTM also considers the potential for a business environmental risk (BER), defined as a risk which can have a material environmental or environmentally driven impact on the business associated with the current or planned use of the Subject Property, not necessarily limited to those environmental issues required to be investigated by the ASTM standard. Consideration of BERs may involve addressing one or more ASTM non-scope considerations.

This Phase I ESA was conducted in accordance with the MSA between Stantec and City Ventures. The scope of work conducted during this Phase I ESA consisted of a visual reconnaissance of the Subject Property, interviews with key individuals, and review of reasonably ascertainable documents. The scope of work did not include an assessment for environmental regulatory compliance of any facility ever operated at the Subject Property (past or present), or sampling and analyzing of environmental media.

Stantec was not contracted to perform an independent evaluation of the purchase or lease price of the Subject Property and its relationship to current fair market value. The conclusions presented in this Phase I ESA report are professional opinions based on data described herein. The opinions are subject to the limitations described in Section 2.3.

ASTM E1527-21 notes that the availability of record information varies from source to source. The User or Environmental Professional (EP) is not obligated to identify, obtain, or review every possible source that might exist with respect to a property. Instead, ASTM identifies record information that is reasonably ascertainable from standard sources. “Reasonably ascertainable” means:

1. Information that is publicly available;

2. Information that is obtainable from its source within reasonable time and cost constraints; and

3. Information that is practicably reviewable.

2.1 SUBJECT PROPERTY DESCRIPTION
The Subject Property consists of approximately 2.74 acres of land developed with a small orchard with orange, avocado, and dragonfruit and three residential structures and support buildings (i.e. garage and storage sheds). Adjoining properties, as well as the nearby area, generally include residential properties and a park. A Subject Property Location Map is provided as Figure 1. A Subject Property Vicinity Map illustrating the main features of the Subject Property and vicinity is provided as Figure 2. Photographs taken during the site reconnaissance visit are provided in Appendix A.

2.2 SPECIAL TERMS, CONDITIONS, AND ADDITIONAL

ASSUMPTIONS
There were no special terms, conditions, or additional assumptions associated with this Phase I ESA.

Page 744 of 2028 ends

19081 YORBA LINDA BOULEVARD
YORBA LINDA, CALIFORNIA 92886
Introduction
Project No.: 185805577 2.3

2.3 EXCEPTIONS AND LIMITING CONDITIONS
This report documents work that was performed in accordance with the MSA. No other representations, warranties or guarantees are made concerning the accuracy or completeness of the data or conclusions contained within this report.

This report provides an evaluation of specified environmental conditions associated with the identified property that was assessed at the time the work was conducted and is based on information obtained by and/or provided to Stantec at that time. 40 CFR 312.20(f)(2) requires that the Environmental Professional evaluate the thoroughness and reliability of provided information. Stantec can neither warrant nor guarantee such thoroughness or reliability, however.

Conclusions made within this report consist of Stantec’s professional opinion as of the time of the preparation of this report, and are based solely on the scope of work described in the report, the limited data available and the results of the work. They are not a certification of the property’s environmental condition.

Project Specific limiting conditions are provided in Section 2.2.

The conclusions are based on the site conditions encountered by Stantec at the time of the work.

Accordingly, additional studies and actions may be required. The identification of non-environmental risks to structures or people on the Property is beyond the scope of this assessment.

Stantec specifically disclaims any responsibility to update the conclusions in this report if new or different information later becomes available or if the conditions or activities on the property subsequently change.

2.4 PERSONNEL QUALIFICATIONS
This Phase I ESA was conducted by, or under the supervision of, an individual that meets the ASTM definition of an EP. The credentials of the EP and other key Stantec personnel involved in conducting this Phase I ESA are provided in Appendix B.

Page 745 of 2028 ends

19081 YORBA LINDA BOULEVARD
YORBA LINDA, CALIFORNIA 92886
User-Provided Information
Project No.: 185805577 3.1

3.0 USER-PROVIDED INFORMATION
ASTM E1527-13 and ASTM E1527-21 describe responsibilities of the User to complete certain tasks in connection with the performance of “All Appropriate Inquiries” into the Subject Property. The ASTM standard requires that the EP request information from the User on the results of those tasks because that information can assist in the identification of RECs, CRECs, HRECs, or de minimis conditions in connection with the Subject Property. Towards that end, Stantec requested that the User provide the following documents and information:

Description of Information
Provided
(Yes /
No) Description and/or Key Findings
User Questionnaire and/or Interview Yes The user is not aware of any environmental issues associated with the Subject Property.

Environmental Liens or Activity and Use
Limitations (AUL)
No No environmental liens and/or AUL were
identified in the Old Republic National Title
Insurance Company title dated January 28,
2022.

Previous Environmental Permits or
Reports Provided by User
Yes Previous reports and documents were
provided for the Subject Property and are
summarized in Section 4.4.6.

Purpose of the Phase I ESA Yes The intended use of the Phase I is for due diligence in support of acquisition for
redevelopment.

Stantec forwarded the ASTM recommended User Questionnaire to Patrick Chien, Development Manager of City Ventures. The completed User Questionnaire returned to us by Mr. Chien and dated April 4, 2022, is included in Appendix C.

Page 746 of 2028 ends

19081 YORBA LINDA BOULEVARD
YORBA LINDA, CALIFORNIA 92886
Records Review
Project No.: 185805577 4.1

4.0 RECORDS REVIEW
The objective of consulting historical sources of information is to develop the history of the Subject Property and surrounding area and evaluate if past uses may have resulted in RECs. Physical setting records are evaluated to determine if the physical setting may have contributed to adverse environmental conditions in connection with the Subject Property. During the review of historical records, Stantec attempted to identify uses of the Subject Property from the present to the first developed use of the Subject Property. Stantec’s research included the reasonably ascertainable and useful records described in this section.

4.1 PHYSICAL SETTING
A summary of the physical setting of the Subject Property is provided in the table below with additional details in the following subsections
Topography: According to the USGS Yorba Linda Topographic Map, the Subject Property is approximately 451 feet above mean sea level (amsl) with a regional topographic gradient to the south southwest (EDR, 2022).

Soil/Bedrock Data: The United States Department of Agriculture – Natural Resources Conservation Service (USDA-NRCS), Web Soil
Survey identifies the soils beneath the Subject Property as Yorba gravelly sandy loam with 2-9 percent slopes,
consisting of well drained, very high runoff soils, with a typical soil profile comprised of gravelly sandy loam (0-11 inches), very gravelly sandy clay loam (11-40 inches), and very gravelly sandy loam (40-63 inches), and a parent
material of sandy and gravelly alluvium derived from mixed material (USDA, 2022).

Estimated Depth to Groundwater/
Estimated Direction of Gradient:

Site specific groundwater investigations were not conducted during this ESA; however, according to a 2000 site closure report for a nearby site approximately 1,700 feet southwest of the Subject Property, groundwater was measured to be approximately 47-70 feet below ground surface (bgs) with a flow direction to the southwest (County of Orange, 2000).

NOTE:

Site-specific groundwater flow direction and depth can only be determined by conducting site-specific testing, which Stantec has not conducted.

4.1.1 Subject Property Topography and Surface Water Flow The Property is located at approximately 451 feet above mean sea level (ft amsl). Based on topography of the area, storm water from the Property is expected to flow towards the south southwest.

Page 747 of 2028 ends

19081 YORBA LINDA BOULEVARD
YORBA LINDA, CALIFORNIA 92886
Records Review
Project No.: 185805577 4.2

4.1.2 Regional and Subject Property Geology
The Property is located within the Coastal Plain of Orange County groundwater basin (8-001). The basin is bound to the north by consolidated rocks of the Puente and Chino Hills, to the east by the Santa Ana Mountains, to the south by the San Joaquin Hills, and to the southwest by the Pacific Ocean. The basin underlies a coastal alluvial plain and the lower Santa Ana River watershed (Coastal Plain of Orange County Groundwater Basin (ca.gov)).

The United States Department of Agriculture – Natural Resources Conservation Service (USDA-NRCS), Web Soil Survey identifies the soils beneath the Subject Property as Yorba gravelly sandy loam with 2-9 percent slopes, consisting of well drained, very high runoff soils, with a typical soil profile comprised of gravelly sandy loam (0-11 inches), very gravelly sandy clay loam (11-40 inches), and very gravelly sandy loam (40-63 inches), and a parent material of sandy and gravelly alluvium derived from mixed material (USDA, 2022).

According to California Department of Conservation’s (DOC) Earthquake Zone Map (Department of Conservation Map Server (ca.gov), the Subject Property is not located within an Alquist-Priolo (AP) Earthquake Fault Zone boundary. The closest fault zone is located approximately two miles to the north of the Subject Property.

4.1.3 Regional and Subject Property Hydrogeology
The Property is located within the Coastal Plain of Orange County groundwater basin (8-001). The basin underlies a coastal alluvial plain and the lower Santa Ana River watershed. The basin is comprised of a deep depression containing fresh water bearing marine and continental sand, silt, and clay, with finer material increasing toward the coast. The majority of surface water recharge occurs within coarser deposits. Sediments that hold fresh water occur to approximately 2,000 feet bgs. Upper, middle, and lower aquifers are present below this level. Basin recharge occurs through Santa Ana River percolation, precipitation, and well injection. Historically, groundwater flow was toward the ocean in the southwest portion of the basin, but pumping caused water levels to fall below sea level inland from the NewportInglewood fault zone. This trough subsequently allowed for ocean water to contaminate groundwater. As a result, injection wells have been placed within the Alamitos and Talbert Gaps (erosional channels) that allow injected water to help protect the basin from seawater (Coastal Plain of Orange County Groundwater Basin (ca.gov).

4.2 FEDERAL, STATE AND TRIBAL ENVIRONMENTAL RECORDS
A regulatory agency database search report was obtained from Environment Data Resources (EDR), a third-party environmental database search firm. A complete copy of the database search report, including

Page 748 of 2028 ends

19081 YORBA LINDA BOULEVARD
YORBA LINDA, CALIFORNIA 92886
Records Review
Project No.: 185805577 4.3
the date the report was prepared, the date the information was last updated, and the definition of databases searched, is provided in Appendix D.

Stantec evaluated the information listed within the database relative to potential impact to the Subject Property, assessing the potential for impacts based in part on the physical setting. As part of this process, inferences have been made regarding the likely groundwater flow direction at or near the Subject Property. As described in 4.1.3, the inferred shallow groundwater flow direction is likely to be in the southwest. Observations about the Subject Property and adjoining properties made during the Subject Property reconnaissance are provided in more detail in Section 5.

4.2.1 Listings for Subject Property
Stantec assessed data presented in the environmental agency database search report to evaluate the potential for conditions on the Property to pose a REC, CREC, or HREC for the Subject Property. The evaluation included an opinion of the potential for contamination by hazardous substances or petroleum products including by vapor migration or encroachment (i.e., potential for a vapor encroachment condition [VEC]).

Listed Facility Name/Address Database Listing REC?
(YES / NO)
Young Family Farm/Young Farm/Joe L. Young and
Joe S. Young
19081 Yorba Lind Blvd.

Yorba Linda, CA

RCRA-SQG, UST, HIST

UST, HWTS, ECHO,

FINDS, RCRA
NonGen/NLR
Yes
The Subject Property lists an historic 550-gallon UST installed in 1962 and containing fuel. This UST was reportedly removed in 2020 based on User-provided records. Additionally, pesticide wastes were also disposed of in 2020. The presence of a UST and waste associated with pesticide use are considered RECs for the Subject Property.

4.2.2 Listings for Adjoining and Nearby Sites with Potential to Impact Subject Property
Stantec assessed data presented in the environmental agency database search report to evaluate the potential for conditions on adjoining and nearby sites to pose a REC, CREC, or HREC for the Subject Property. The evaluation included an opinion of the potential for contamination by hazardous substances or petroleum products to migrate to the Subject Property from an adjoining or nearby site, including by vapor migration or encroachment (i.e., potential for a vapor encroachment condition [VEC].

The remaining listings in the database search report, including listings of Orphan Sites, provided in Appendix D, do not constitute a potential REC for the Subject Property.

Page 749 of 2028 ends

19081 YORBA LINDA BOULEVARD
YORBA LINDA, CALIFORNIA 92886
Records Review
Project No.: 185805577 4.4

4.3 LOCAL/REGIONAL ENVIRONMENTAL RECORDS
Stantec checked the following sources to obtain information pertaining to Subject Property use and/or indications of RECs in connection with the Subject Property:

Page 750 of 2028 ends

19081 YORBA LINDA BOULEVARD
YORBA LINDA, CALIFORNIA 92886
Records Review
Project No.: 185805577 4.5

4.3.1 Local Health Department
Agency Name, Contact Information,
Date Finding
Custodian of Records
County of Orange Health Care
Agency
Via email:

Custodian of Records | Orange
County California - Health Care
Agency (ochealthinfo.com)
April 4, 2022
A written request subject to the Freedom of Information Act (FOIA) was submitted to the County of Orange Health Care Agency (OCHCA) to review their files regarding the Subject Property. The information requested included file information regarding permits, hazardous materials, waste, complaints, violations, underground or aboveground storage tanks,
remedial action, and case closure documentation, or any records that indicate environmental concern at the Subject Property.

On April 11, 2022, the agency responded with UST removal documentation in 2020. The OCHCA issued a “Completion of Tank Removal Project” letter dated June 2, 2020. A copy of this letter is provided in Appendix F.

According to a Underground Storage Tank Removal
Documentation report prepared by APTIM Environmental and Infrastructure LLC (APTIM) dated May 15, 2020, a 500-gallon gasoline underground storage tank was located in the
northwestern area of the Property and beneath a small storage shed and was installed in the 1960s without a permit. The UST was removed under the oversight of the OCHCA and was
observed in good condition without any staining or odors.

Under the direction of the on-site OCHCA inspector, two soil samples were collected from beneath the UST at the north and south end of the excavation at approximately 5-feet bgs. The samples were analyzed for total petroleum hydrocarbons as gasoline (TPHg)and full list volatile organic compounds (VOC).

Concentrations were reported of TPHg at 0.27 milligrams per kilogram (mg/kg); Xylenes at 0.0091 mg/kg; and Toluene at

0.012 mg/kg. The excavation was backfilled with clean
overburden on-site import soil. Based on these results no further action was recommended. Based on this data, the Orange County Health Care Agency provided a case closure letter dated June 2, 2020, for the former UST.

Page 751 of 2028 ends

19081 YORBA LINDA BOULEVARD
YORBA LINDA, CALIFORNIA 92886
Records Review
Project No.: 185805577 4.6

4.3.1 California Geologic Energy Management Division (CalGEM) Agency Name, Contact
Information
Findings
California Geologic Energy
Management Division (CalGEM),
Department of Conservation
5816 Corporate Avenue, Suite 200
Cypress, CA 90630
Online database:
https://maps.conservation.ca.gov/
doggr/wellfinder/#openModal
Date Accessed: April 4, 2022
The California Department of Conservation Geologic Energy Management Division (CalGEM, formerly, the Division of Oil, Gas, and Geothermal Resources [DOGGR]) website
(https://www.conservation.ca.gov/calgem/Pages/WellFinder.aspx) was searched to identify the potential existence of oil and gas production wells within the vicinity of the Subject Property. The Subject Property appears to lie within the Yorba Linda Oil/Gas Field. The nearest well is located approximately 1,000 feet west of the Subject Property. This well, “Apalategui 1”, leased by ACOP Inc., was drilled and subsequently plugged and
abandoned in 1956. No records of spills, leaks, or violations were reported; therefore, this well is not considered a REC for the Property.

4.3.2 Fire Department
Agency Name,
Contact Information, Date Finding
Custodian of Records
Orange County Fire Authority
1 Fire Authority Road
Irvine, CA 92602
Via email:

OCFA - Orange County Fire Authority
April 4, 2022
A written request subject to the FOIA was submitted to the San Bernardino County Fire Protection District to review their files regarding the Subject Property. The information
requested included file information regarding permits,
hazardous materials, waste, complaints, violations,
underground or aboveground storage tanks, remedial action, and case closure documentation, or any records that indicate environmental concern at the Subject Property.

On April 5, 2022, the agency responded with inspection
records for the adjacent church (19045 Yorba Linda) with no environmental significance. There were no records for the Subject Property address.

4.3.3 Local Building and/or Planning Department Records Agency Name, Contact Information,
Date Findings
Custodian of Records
City of Yorba Linda
Via email: [email protected]
April 5, 2022
A written request subject to the FOIA was submitted to the City of Yorba Linda to review their files regarding the Subject Property. The information requested included file information regarding permits, hazardous materials, waste, complaints, violations, underground or aboveground storage tanks,
remedial action, and case closure documentation, or any

Page 752 of 2028 ends

19081 YORBA LINDA BOULEVARD
YORBA LINDA, CALIFORNIA 92886
Records Review
Project No.: 185805577 4.7
Agency Name, Contact Information,
Date Findings
records that indicate environmental concern at the Subject Property.

On April 8, 2022, the agency responded with building and plumbing permits associated with the Subject Property. No records of environmental significance were observed.

4.3.4 Local/Regional Pollution Control Agency Department Records Agency Name, Contact Information,
Date Findings
Custodian of Records
Department of Toxic Substances
Control (DTSC)
Via email:

[email protected]
Online database:

EnviroStor (ca.gov)
April 4, 2022
A written request subject to the FOIA was submitted to
Cypress Regional Office of the DTSC to review their files regarding the Subject Property. The information requested included file information regarding permits, hazardous
materials, waste, complaints, violations, underground or aboveground storage tanks, remedial action, and case
closure documentation, or any records that indicate
environmental concern at the Subject Property.

On April 7, 2022, the DTSC responded with no records for the Subject Property. Additionally, there were no records on the DTSC online database Envirostor.

4.3.5 Local/Regional Water Quality Agency Records
Agency Name, Contact Information,
Date Findings
Custodian of Records
Regional Water Quality Control Board
(RWQCB)
Online database:

GeoTracker (ca.gov)
April 4, 2022
A written request subject to the FOIA was submitted to the RWQCB to review their files regarding the Subject Property.

The information requested included file information regarding permits, hazardous materials, waste, complaints, violations, underground or aboveground storage tanks, remedial action, and case closure documentation, or any records that indicate environmental concern at the Subject Property.

On April 7, 2022, the RWQCB responded with no records for the Subject Property. Additionally, there were no records on the RWQCB online database Geotracker.

Page 753 of 2028 ends

19081 YORBA LINDA BOULEVARD
YORBA LINDA, CALIFORNIA 92886
Records Review
Project No.: 185805577 4.8

4.4 HISTORICAL RECORDS REVIEW

4.4.1 Land Title Records/Deeds
No environmental liens and/or AUL were identified in the Old Republic National Title Insurance Company title dated January 28, 2022. No other land title records, deeds, environmental liens, and activity and use limitation documentation was not provided by the User, and public records were not searched by Stantec.

4.4.2 Aerial Photographs
Stantec reviewed historical aerial photographs provided by EDR. The general type of activity on a property and land use changes can often be discerned from the type and layout of structures visible in the photographs. However, specific elements of a facility's operation usually cannot be discerned from aerial photographs alone. The following table summarizes Stantec’s observations of the reviewed historical aerial photographs.

Year Scale Observations of Subject Property and Adjoining/Nearby Properties 1938
1946
1953
1” = 500’ The Subject Property and vicinity appear to be agricultural land. The Subject Property appears bound to the south by a road. Scattered residential buildings are depicted in the vicinity.
1963
1966
1” = 500’ The Subject Property appears developed with 2-3 structures and agricultural land. The vicinity appears to be agricultural with associated buildings and residential houses.
1972
1977
1985
1989
1994
2002
2005
2009
2012
2016
1” = 500’ The Subject Property appears similar to the 1966 photograph. Residential development increases throughout the vicinity. A park appears adjacent to the east by 1985.

Name of aerial photograph source: EDR, Appendix E. No RECs were noted during the review of the historical aerial photographs.

4.4.3 City Directories
Stantec retained a third party to research available city directories for the Subject Property and adjoining and nearby properties, in approximately five-year intervals. The Subject Property is listed in the City Directory as “Lui H. Young” in 2014-2005 and “Joe S. Young” in 2000,1987 1982, 1976, 1973, and 1965.

Nearby properties generally include residential and commercial listings.

Page 754 of 2028 ends

19081 YORBA LINDA BOULEVARD
YORBA LINDA, CALIFORNIA 92886
Records Review
Project No.: 185805577 4.9
Name of city directories and source: EDR, Appendix E
No RECs were noted during the review of the City Directories.

4.4.4 Historical Fire Insurance Maps
Fire insurance maps were developed for use by insurance companies to depict facilities, properties, and their uses for many locations throughout the United States. These maps provide information on the history of prior land use and are useful in assessing whether there may be potential environmental contamination on or near the Subject Property. These maps, which have been periodically updated since the late 19th century, often provide valuable insight into historical Subject Property and adjoining and nearby property uses.

Stantec requested fire insurance maps from EDR; however, no coverage exists for the Subject Property.

The Sanborn® Map Search Report indicating “no coverage” is presented in Appendix E.

4.4.5 Historical Topographic Maps
Stantec reviewed the historical USGS 7.5-minute Topographic Maps of the Yorba Linda and Orange, California Quadrangles (scale 1:24,000), the historical USGS 7.5-minute Topographic Maps of the Orange and Olinda, California Quadrangles (scale 1:31,680), the historical USGS 15-minute Topographic Maps of the Anaheim, California Quadrangles (scale 1:62,500), the historical USGS 15- minute Topographic Maps of the Anaheim, California Quadrangles (scale 1:50,000), and the historical USGS 30-minute Topographic Maps of the Corona, California Quadrangles (scale 1:125,000), to help identify past Subject Property and adjoining and nearby property usage and areas of potential environmental concern. Copies of the historical maps are provided in Appendix E.

The following table summarizes the maps reviewed and our observations.

Year Scale
Observations of Subject Property and Adjoining/Nearby
Properties
1896
1898
1901
1902
1:62,500
1:62,500
1:62,500
1:125,000
The Subject Property and vicinity are depicted as vacant land. 1935 1:31,680 The Subject Property appears vacant and bound by a road to the south. Several roads and structures are depicted throughout the vicinity.
1942
1949
1950
1:50,000
1:24,000
1:24,000
The Subject Property and vicinity appear to be agricultural land. 1964
1972
1981
1:24,000
1:24,000
1:24,000
The Subject Property appears to contain three structures. Agricultural and residential development are shown throughout the vicinity.

Page 755 of 2028 ends

19081 YORBA LINDA BOULEVARD
YORBA LINDA, CALIFORNIA 92886
Records Review
Project No.: 185805577 4.10
Year Scale
Observations of Subject Property and Adjoining/Nearby
Properties
2012
2015
2018
1:24,000
1:24,000
1:24,000
Structures are not depicted on the map.

Name of maps and source: EDR, Appendix E
No RECs were noted during the review of the topographic maps.

4.4.6 Other Historical Sources
Stantec was provided with the following previous reports and documents for the Subject Property:

Limited Environmental Site Assessment and Subsurface Investigation, Young Farm, 19081 Yorba Linda, California, dated June 30, 2020 prepared by APTIM Environmental and Infrastructure, LLC.

This report documented the 500-gallopn underground storage tank removal and removal of various containers of known and unknown hazardous waste stored on-site in 2019. Four areas of potential concern were identified in 2019 and included two small storage sheds, an outdoor drum storage area, and an outdoor miscellaneous container storage area. The storage sheds were generally used to store various chemicals including pesticides and herbicides. The UST was located beneath one of the sheds.

Two 55-gallon drums were stored in the northwestern corner of the Subject Property. Several small containers of various types of wastes were placed along the western property border.

The removal of the 500-gallon UST occurred in April 2020 under the oversight of the OCHCA. Based on the assessment data, the Orange County Health Care Agency provided a case closure letter dated June 2, 2020, for the former UST.

On April 27, 2020, APTIM removed the identified hazardous waste (i.e. pesticides, herbicides, oily water, empty drums, flammable toxic liquids, corrosive inorganic acidic liquids, acetic acid, inorganic nitrates, and toxic solid inorganics) from the Subject Property and were disposed off-site under manifests. Two 55-gallon drums were observed in the northwest corner and showed signs of significant corrosion including ground staining. One of the drums was empty and the other drum had approximately 30-gallons of oily water. Six soil samples were collected at 1 and 2.5-feet bgs from the areas of concern and were analyzed for volatile organic compounds, total petroleum hydrocarbons, semi-volatile organic compounds, pesticides, organochlorine pesticides, and herbicides.

Analytical results showed only minor detections including total petroleum hydrocarbons as diesel at 16 milligrams per kilogram (mg/kg); total petroleum hydrocarbons as motor oil at 240 mg/kg; 4,4’-DDD at 18 mg/kg; 4,4’-DDE at 13 mg/kg; 4,4’-DDT at 38 mg/kg; and toxaphene at 330 mg/kg. Based on these results, APTIM concluded that no unacceptable risk to human health or the environment was identified.

Page 756 of 2028 ends

19081 YORBA LINDA BOULEVARD
YORBA LINDA, CALIFORNIA 92886
Site Reconnaissance
Project No.: 185805577 5.1

5.0 SITE RECONNAISSANCE
A visit to the Subject Property and its vicinity was conducted by Alicia Jansen (Stantec) on April 11, 2022.

Stantec was accompanied by Mr. Steve Young, representative of the Property Owner, during the Subject Property visit. Figure 2 provides information about the Subject Property and adjoining sites and the location of potential areas of environmental concern. Photographs collected during the site reconnaissance are included in Appendix A.

5.1 SITE RECONNAISSANCE METHODOLOGY
The site reconnaissance focused on observation of current conditions and observable indications of past uses and conditions of the Subject Property that may indicate the presence of RECs. The reconnaissance of the Property was conducted on foot and Stantec utilized the following methodology to observe the Property:
• Traverse the outer Subject Property boundary
• Traverse transects across the Subject Property
• Traverse the periphery of all structures on the Subject Property • Visually observe accessible interior areas expected to be used by occupants or the public maintenance and repair areas, utility areas, and a representative sample of occupied spaces Weather conditions during the visit to the Subject Property were clear and sunny. There were no weatherrelated Subject Property access restrictions encountered during the reconnaissance visit.

5.2 GENERAL DESCRIPTION
Subject Property and Area
Description:

The Subject Property is located north of Yorba Linda Boulevard, in the City of Yorba Linda, County of Orange, California. The surrounding area consists of residential structures, a church, and a public park.

Subject Property
Operations:

Residential and orchards.

Structures, Roads, Other
Improvements:

The Subject Property is currently developed with three residential structures, a garage, storage sheds, and orchards.

Subject Property Size
(acres):

Approximately 2.74 acres
Estimated % of Subject
Property Covered by
Buildings and/or Pavement:
20%
Observed Current Subject
Property Use/Operations:

The Subject Property is currently developed with three residential structures, a garage, storage sheds, and orchards.

Observed Evidence of Past
Subject Property Use(s):

Orchards and hot houses.

Page 757 of 2028 ends

19081 YORBA LINDA BOULEVARD
YORBA LINDA, CALIFORNIA 92886
Site Reconnaissance
Project No.: 185805577 5.2
Sewage Disposal Method
(and age):

There are three septic tanks located south of the residential structures.

Potable Water Source: City of Yorba Linda.

Electric and Natural Gas
Utilities:

Southern California Edison.

5.3 HAZARDOUS SUBSTANCES AND PETROLEUM PRODUCTS
The following table summarizes Stantec’s observations during the Subject Property reconnaissance.

Observations Description/Location
Hazardous Substances and
Petroleum Products as Defined by
CERCLA 42 U.S.C. § 9601(14) with
identified uses:

Small amounts of pesticides (i.e. Roundup), gasoline (5-gallon containers), and oil were observed in the garage and storage shed. The containers appeared in good condition without any evidence of leaking or staining.

Drums/Totes/Intermediate Bulk
Containers (≥ 5 gallons):

None observed
Strong, Pungent, or Noxious
Odors:

None observed
Pools of Liquid: None observed
Unidentified Substance Containers: None observed
Polychlorinated biphenyl (PCB)-
Containing Equipment:

None observed
Other Observed Evidence of
Hazardous Substances or
Petroleum Products:

None observed

5.4 INTERIOR OBSERVATIONS
Stantec made the following observations during the site reconnaissance of the building interiors at the Subject Property and/or identified the following information during the interview or records review portions of the assessment:

Observations Description
Heating/Cooling Method: None observed
Surface Stains or Corrosion: None observed
Floor Drains and Sumps: None observed
Other Interior Observations: None observed

Page 758 of 2028 ends

19081 YORBA LINDA BOULEVARD
YORBA LINDA, CALIFORNIA 92886
Site Reconnaissance
Project No.: 185805577 5.3

5.5 EXTERIOR OBSERVATIONS
Stantec made the following observations during the site reconnaissance of exterior areas of the Subject Property and/or identified the following information during the interview or records review portions of the assessment:

Observations Description
On-site Pits, Ponds, or Lagoons: None observed
Stained Soil or Pavement: None observed
Stressed Vegetation: None observed
Waste Streams and Waste
Collection Areas:

None observed
Solid Waste Disposal: No areas indicative of solid waste disposal were observed.

Potential Areas of Fill Placement: No mounds, piles, or depressions suggesting the placement of fill material were observed on the Subject Property.

Wastewater: No exterior wastewater discharge was observed.

Stormwater: Based on the topography, stormwater is anticipated to flow from the northern Subject Property line toward the southsouthwest. According to the Property Owner Representative, there was a former issue with off-site stormwater from the adjacent park that flooded the orchards in the center of the Subject Property.

Wells: No wells were observed.

Septic Systems: There are three septic tanks located south of the residential structures.

Other Exterior Observations: None.

5.6 UNDERGROUND STORAGE TANKS/STRUCTURES
Existing
USTs:

No visible evidence (fill pipes, vent pipes, dispensers, surface patches), which would indicate the presence of USTs, was discovered during the site reconnaissance.

Former
USTs:

A former 500-gallon gasoline UST was located in the northwestern portion of the Subject Property. This UST is discussed in detail in Section 4.0 above.

Other
Underground
Structures:

None observed.

5.7 ABOVEGROUND STORAGE TANKS
Existing
ASTs:

No visible evidence (fill pipes, vent pipes, dispensers, surface stains), which would indicate the presence of ASTs, was discovered during the site reconnaissance.

Page 759 of 2028 ends

19081 YORBA LINDA BOULEVARD
YORBA LINDA, CALIFORNIA 92886
Site Reconnaissance
Project No.: 185805577 5.4
Former
ASTs:

No visible evidence (fill pipes, vent pipes, dispensers, surface stains), reports, or other evidence of the former presence of ASTs was discovered during this Phase I ESA.

5.8 ADJOINING PROPERTIES

5.8.1 Current Uses of Adjoining Properties
As viewed from the Subject Property and/or from public rights-of-way, Stantec made the following observations about use and activities on adjoining sites:

NORTH Residential
EAST Public Park.

SOUTH Residential and Yorba Linda Boulevard beyond which are more residential properties.

WEST Residential, vacant lot, and a church.

5.8.2 Observed Evidence of Past Uses of Adjoining Properties Observations of adjoining sites providing indications of past use and activities, if any, are described below.

NORTH None observed.

EAST None observed.

SOUTH None observed.

WEST None observed.

5.8.3 Pits, Ponds or Lagoons on Adjoining Properties
As viewed from the Subject Property and/or from public rights-of-way, Stantec made the following observations about the presence of pits, ponds, and lagoons on adjoining sites:

NORTH None observed.

EAST None observed.

SOUTH None observed.

WEST None observed.

5.9 OBSERVED PHYSICAL SETTING
Topography of the
Subject Property and
Surrounding Area:

The topography of the subject Property and surrounding lands trend downslope from northeast to southwest.

Page 760 of 2028 ends

19081 YORBA LINDA BOULEVARD
YORBA LINDA, CALIFORNIA 92886
Interviews
Project No.: 185805577 6.1

6.0 INTERVIEWS
Stantec conducted interviews with the following individuals:

Name, Contact Information,
and Date of Interview
Relationship to Subject
Property Key findings:

Wah Ging “Steve Young” Property Owner Representative Mr. Young is not aware of any petroleum spills, notices of
violation, or environmental
issues associated with the
Subject Property. Mr. Young is
not aware of any widespread
use of pesticides on the Subject
Property.

Page 761 of 2028 ends

19081 YORBA LINDA BOULEVARD
YORBA LINDA, CALIFORNIA 92886
Evaluation
Project No.: 185805577 7.1

7.0 EVALUATION
This section provides a summary overview of or Findings, Opinions, and Conclusions.

7.1 FINDINGS AND OPINIONS
Information gathered from interviews, reviews of existing data, and an inspection was evaluated to determine if RECs are present in connection with the Subject Property. Based on this information, Stantec made the following findings and developed the following opinions. • The majority of the Subject Property is utilized as an orange, avocado, and dragon fruit orchard; the Subject Property has been agricultural in use since at least the 1930s. Application of pesticides and herbicides is considered likely to have occurred during this time period, potentially resulting in the accumulation of pesticides and metals common with herbicide application in shallow soils at the Subject Property. Therefore, the former and current agricultural activity on the Subject Property is considered a REC. Stantec recommends performing a shallow soil investigation on the Subject Property.
• Based on review of historical documents including regulatory records, the Subject Property formerly contained a 500-gallon gasoline UST, multiple hazardous waste containers, and contaminated soil that were removed in 2020. Shallow soil sampling was also performed at this time; contaminants were not reported above residential screening levels. However, soil vapor sampling was not conducted at the Subject Property. This represents a potential vapor encroachment condition (VEC) and is considered a REC for the Subject Property. It is recommended that a Phase II subsurface investigation be conducted to further evaluate the potential of a REC.
• An environmental records search was performed and identified sites within their respective ASTM E1527-21 search radii of the Subject Property that may represent RECs, CRECs, HRECs, or de minimis conditions.

Based on one or more of the following reasons: distance from the Subject Property, position of sites with respect to assumed groundwater flow direction, the type of native soils, and regulatory status, none of the sites identified in the environmental records search report are expected to impact soil or groundwater quality at the Subject Property. The environmental records search identified no RECs, CRECs, HRECs or de minimis conditions at or near the Subject Property.

7.2 DATA GAPS
The federal AAI final rule [40 CFR 312.10(a)] and ASTM E1527-21 identify a “data gap” as the lack or inability to obtain information required by the standards and practices of the rule despite good faith efforts by the EP or the User.

Any data gaps resulting from the Phase I ESA described in this report are listed and discussed below.

Page 762 of 2028 ends

19081 YORBA LINDA BOULEVARD
YORBA LINDA, CALIFORNIA 92886
Evaluation
Project No.: 185805577 7.2
Gap Discussion
Deletions or Exceptions from
Scope of Work Referenced in
Section 1.4:

None.

Weather-Related Restrictions to
Site Reconnaissance:

None.

Facility Access Restrictions to
Site Reconnaissance:

None.

Other Site Reconnaissance
Restrictions:

None.

Data Gaps from Environmental
Records Review:

None.

Data Gaps from Historical
Records Review:

None.

Data Gaps from Interviews: None.

Other Data Gaps: None.

7.3 CONCLUSIONS
We have performed a Phase I ESA in conformance with the scope and limitations of ASTM Practice E1527-21 and E1527-13 of the Subject Property. Any exceptions to, or deletions from, this practice are described in Section 2.3 of this report. This assessment has revealed the following evidence of recognized environmental conditions (RECs) with the Subject Property:
• The Subject Property formerly contained a 500-gallon gasoline UST, multiple hazardous waste containers, and contaminated soil that were removed in 2020. Shallow soil sampling was also performed at this time; contaminants were not reported above residential screening levels.

However, soil vapor sampling was not conducted at the Subject Property. This represents a potential vapor encroachment condition (VEC) and is considered a REC for the Subject Property.

It is recommended that a Phase II subsurface investigation be conducted to further evaluate the potential of a REC.
• The majority of the Subject Property is utilized as an orange, avocado, and dragon fruit orchard; the Subject Property has been agricultural in use since at least the 1930s. Application of pesticides and herbicides is considered likely to have occurred during this time period, potentially resulting in the accumulation of pesticides and metals common with herbicide application in shallow soils at the Subject Property. Therefore, the former and current agricultural activity on the Subject Property is considered a REC. Stantec recommends performing a shallow soil investigation on the Subject Property.

Page 763 of 2028 ends

19081 YORBA LINDA BOULEVARD
YORBA LINDA, CALIFORNIA 92886
Non-Scope Considerations
Project No.: 185805577 8.1

8.0 NON-SCOPE CONSIDERATIONS
The following ASTM E1527-13 non-scope services were performed as part of this Phase I ESA:

8.1 LEAD-BASED PAINT
Concern for LBP is primarily related to residential structures. The EPA’s Final Rule on Disclosure of LeadBased Paint in Housing (40 CFR Part 745) defines LBP as paint or other surface coatings that contain lead equal to or in excess of 1.0 milligram per square centimeter or 0.5 percent by weight.

The risk of lead toxicity in LBP varies based upon the condition of the paint and the year of its application.

The U.S. Department of Housing and Urban Development (HUD) has identified the following risk factors:
• The age of the dwelling as follows:
− Maximum risk is from paint applied before 1950.
− There is severe risk from paint applied before 1960.
− There is moderate risk from deteriorated paint applied before 1970. − There is slight risk from the paint that is intact but applied before 1977. • The condition of the painted surfaces.
• The presence of children and certain types of households in the building. • Previously reported cases of lead poisoning in the building or area.

The Subject Property structures were constructed in the 1960s; an LBP survey is recommended prior to renovation activities.

8.2 ASBESTOS
Asbestos can be found in many applications, including sprayed-on or blanket-type insulation, pipe wraps, mastics, floor and ceiling tiles, wallboard, mortar, roofing materials, and a variety of other materials commonly used in construction. The greatest asbestos-related human health risks are associated with friable asbestos, which is ACM that can be reduced to powder by hand pressure. Friable asbestos can become airborne and inhaled, which has been associated with specific types of respiratory disease. The manufacturing and use of asbestos in most building products was curtailed during the late 1970s.

The Subject Property structures were constructed in the 1960s; an ACM survey is recommended prior to renovation activities.

8.3 RADON
Radon is a colorless, tasteless radioactive gas with an EPA-specified action level of 4.0 PicoCuries per liter of air (pCi/L) for residential properties. Radon gas has a very short half-life of 3.8 days. The health risk potential of radon is primarily associated with its rate of accumulation within confined areas near or in the ground, such as basements, where vapors can readily transfer to indoor air from the ground through

Page 764 of 2028 ends

19081 YORBA LINDA BOULEVARD
YORBA LINDA, CALIFORNIA 92886

Project No.: 185805577 8.2
foundation cracks or other pathways. Large, adequately ventilated rooms generally present limited risk for radon exposure. The radon concentrations in buildings and homes depend on many factors, including soil types, temperature, barometric pressure, and building construction (EPA, 1993).

Stantec reviewed regional data published by the EPA on average indoor radon concentrations in the vicinity of the Property (http://www.epa.gov/radon/zonemap.html).

EPA Radon Zones (w/Average Measured Indoor Radon concentrations) Zone 1 – High
(>4.0 pCi/L)
Zone 2 – Moderate
(2 to 4 pCi/L)
Zone 3 – Low
(<2 pCi/L)
X
Normally occupied sub grade areas present? (i.e., basement apartments, offices, stores, etc.) No subgrade areas currently present at the Property.

The Subject Property is located in Zone 2 and is considered to have a moderate potential for radon. To determine Subject Property-specific radon levels, a radon survey would have to be conducted. However, because the Subject Property does not have any occupied subgrade areas and is planned for redevelopment, further investigation of indoor radon issues does not appear to be warranted.

8.4 FLOOD ZONES
According to the Physical Setting summary portion of the EDR report, the Subject Property is not located within a flood hazard zone.

Page 765 of 2028 ends

19081 YORBA LINDA BOULEVARD
YORBA LINDA, CALIFORNIA 92886
References
Project No.: 185805577 9.3

9.0 REFERENCES
ASTM International, 2015, Standard Guide for Vapor Encroachment Screening on Subject Property Involved in Real Estate Transactions, Designation E 2600-15.

ASTM International, 2021, Standard Practice for Environmental Site Assessments: Phase 1 Environmental Site Assessment Process, Designation: E 1527-21.

Environmental Data Resources (EDR), 2022, Aerial Photographs, City Directories, Sanborn® Map Report, Topographic Maps, EDR Radius Map Report with GeoCheck®, Property, 9076 Hyssop Drive, Rancho Cucamonga, CA 91730. Inquiry Number 6927335.2s. April 5.

United States Environmental Protection Agency (EPA), 2005. All Appropriate Inquiries Final Rule.

EPA, 1993. USEPA Map of Radon Zones Throughout United States, Document No. EPA-402-R-93-071.

Websites:
http://Geotracker.swrcb.ca.gov/
https://maps.conservation.ca.gov/doggr/wellfinder/#close https://www.envirostor.dtsc.ca.gov/public/
https://websoilsurvey.sc.egov.usda.gov/App/HomePage.htm Coastal Plain of Orange County Groundwater Basin (ca.gov) https://www.conservation.ca.gov/calgem/Pages/WellFinder.aspx

Page 766 of 2028 ends

19081 YORBA LINDA BOULEVARD
YORBA LINDA, CALIFORNIA 92886
Project No.: 185805577

FIGURES

Page 767 of 2028 ends

Page 768 of 2028 ends

Page 769 of 2028 ends

19081 YORBA LINDA BOULEVARD
YORBA LINDA, CALIFORNIA 92886
Project No.: 185805577

APPENDICES

Page 770 of 2028 ends

19081 YORBA LINDA BOULEVARD
YORBA LINDA, CALIFORNIA 92886
Appendix A Photographs of the Subject Property and Vicinity Project No.: 185805577 A.1
Appendix A Photographs of the Subject Property and
Vicinity

Page 771 of 2028 ends