Corona City Council
July 1, 2026

December 2015 4.B. Air Quality
City of Corona Skyline Heights Project
PCR Services Corporation/SCH No. 2014021003 4.B-35
Distribution centers: CARB also recommends avoiding siting new sensitive land uses within 1,000 feet of a distribution center. The project would not result in a new distribution center. The project would also not be located within 1,000 feet of a distribution center. Uses within 1,000 feet of the project site include primarily residential, school, and commercial uses.

Fueling stations: CARB recommends avoiding new sensitive land uses within 300 feet of a large fueling station (a facility with a throughput of 3.6 million gallons per year or greater). A 50- foot separation is recommended for typical gas dispensing facilities. The project does not include any fueling stations. The project would also not be located within 300 feet of a gas dispensing facility.

The nearest gas dispensing facility is located to the north of the project site near State Route 91. Dry cleaning operations: CARB recommends avoiding siting new sensitive land uses within 300 feet of any dry cleaning operation that uses perchloroethylene. For operations with two or more machines, CARB recommends a buffer of 500 feet. For operations with three or more machines, CARB recommends consultation with the local air district. The project would not result in a new dry cleaning operation. The project would also not be located within 500 feet of a dry cleaning operation that uses perchloroethylene. Based on a search of local dry cleaners in the project area, one dry cleaner is located in close proximity to the project site (Mr. Dry Clean located at 2621 Green River Road). According to facility permitting records from the SCAQMD’s Facility Information Detail (FIND) database, the dry cleaner is not permitted to use equipment containing carcinogenic TACs listed in SCAQMD Rule 1401, Table 1, as amended on March 4, 2005, which includes perchloroethylene.19 Based on the above analysis, the project would meet the CARB recommendations for distances between sensitive receptors and substantial sources of air pollution. Therefore, the project would result in a less than significant impact to sensitive receptors from project operation. (5) Odors
Threshold 5 Would the project create objectionable odors affecting a substantial number of people? Impact 4.B-5 The project would not create objectionable odors affecting a substantial number of people.

Therefore, odors associated with project construction and operation would be less than significant.

According to the SCAQMD CEQA Air Quality Handbook, land uses associated with odor complaints typically include agricultural uses, wastewater treatment plants, food processing plants, chemical plants, composting areas, refineries, landfills, dairies, and fiberglass molding facilities. The project does not include any uses identified by SCAQMD as being associated with odors and therefore would not produce objectionable odors Construction of the project would result in emissions of DPM and VOCs, which may be objectionable to some people. However, the project would comply with the CARB anti-idling regulation that limits idling to 5 minutes at any location and with SCAQMD rules that regulate the VOC content of architectural coatings.

Furthermore, emissions would disperse rapidly from the project site and therefore should not reach an 19 South Coast Air Quality Management District, Facility Information Detail (FIND), Facility ID 86193, http://www3.aqmd.gov/webappl/fim/prog/search.aspx. Accessed October 2014.

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objectionable level for a substantial number of people. Therefore, the project would be expected to result in substantial odorous emissions and impacts would be less than significant. (6) Consistency with Regulatory Framework
Threshold 6 Would the project conflict with any applicable plan, policy, or regulation of an agency with jurisdiction over the project (including, but not limited to, the general plan and municipal code) adopted for the purpose of avoiding or mitigating an environmental effect? Impact 4.B-6 Implementation of the proposed project would not conflict with any applicable plan, policy, or regulation of an agency with jurisdiction over the project (including, but not limited to the General Plan and Municipal Code). This impact is considered less than significant.

Table 4.B-10, General Plan Consistency Analysis, provides an analysis of the project’s consistency with the applicable goals and policies contained in Chapter 5, Environmental Resources, of the City’s General Plan relative to air quality. As discussed in Table 4.B-10, the project would be consistent with the applicable General Plan goals and policies. Furthermore, as discussed above under Impact 4.B-1, the proposed project would not conflict with the applicable AQMP. As such, impacts related to consistency with applicable plans and regulations would be considered less than significant.

3. CUMULATIVE IMPACTS
The SCAQMD’s approach for assessing cumulative impacts is based on the AQMP forecasts of attainment of ambient air quality standards made in accordance with the requirements of the federal and state Clean Air Acts. Therefore, the area of analysis for cumulative impacts on air quality is the entire Basin. As previously discussed, the project would be consistent with the AQMP, which is intended to bring the Basin into attainment for all criteria pollutants.20 The mass regional emissions calculated for the project and presented earlier in this analysis would not exceed the applicable SCAQMD daily significance thresholds, which are designed to assist the region in attaining the applicable state and national ambient air quality standards. The project would comply with SCAQMD’s Rule 403 (fugitive dust control) during construction as well as all other adopted AQMP emissions control measures. As such, the project’s contribution to cumulative impacts would be less than significant. 20 State CEQA Guidelines Section 15064(h)(3) states “A lead agency may determine that a project's incremental contribution to a cumulative effect is not cumulatively considerable if the project will comply with the requirements in a previously approved plan or mitigation program (including, but not limited to, water quality control plan, air quality attainment or maintenance plan, integrated waste management plan, habitat conservation plan, natural community conservation plan, plans or regulations for the reduction of greenhouse gas emissions) which provides specific requirements that will avoid or substantially lessen the cumulative problem within the geographic area in which the project is located. Such plans or programs must be specified in law or adopted by the public agency with jurisdiction over the affected resources through a public review process to implement, interpret, or make specific the law enforced or administered by the public agency. When relying on a plan or program, the lead agency should explain how the particular requirements in the plan or program ensure that the project’s incremental contribution to the cumulative effect is not cumulatively considerable. If there is substantial evidence that the possible effects of a particular project are still cumulatively considerable notwithstanding that the project complies with the specified plan or mitigation program addressing the cumulative problem, an EIR must be prepared for the project.”

December 2015 4.B. Air Quality
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4. MITIGATION MEASURES
Construction and operation of the project would result in less-than-significant air quality impacts. As such, no mitigation measures are required.

5. LEVEL OF SIGNIFICANCE AFTER MITIGATION
Impacts related to air quality would be less than significant.

4.B. Air Quality December 2015
City of Corona Skyline Heights Project PCR Services Corporation/SCH No. 2014021003 4.B-38 Table 4.B-10
General Plan Consistency Analysis
Goals and Policies Consistency
Environmental Resources - Air Quality
Goal 10.18 – Improve air quality conditions within
the Corona Planning Area by controlling point
sources, reducing vehicle trips, and striving to
achieve attainment of ozone, nitrogen dioxide,
carbon monoxide, and sulfate standards as enforced
by the South Coast Air Quality Management District.

Consistent. A full analysis of construction and operational impacts related to air quality and greenhouse gas emissions was prepared for the proposed project, as provided in the Air Quality and Greenhouse Gas Report, Skyline Heights Project, prepared by Michael Brandman Associates, dated May 2014 (provided under separate cover). As indicated in the analysis of air quality impacts, the project would not conflict with applicable air quality plans, would comply with applicable CARB and SCAQMD rules and regulations, and would result in less than significant air quality impacts. The project would not conflict with measures to reduce on- and off-road construction emissions from heavy-duty diesel trucks and equipment, comply with anti-idling provisions for heavy-duty trucks, implement fugitive dust control measures in accordance with SCAQMD Rule 403, and comply with building energy efficiency standards including the California Green Building Standards (see Section 4.F, Greenhouse Gas Emissions). The project would also minimize air pollution by using of low-pollutant emitting interior finish materials for paints, carpet, vinyl flooring and particleboard, as required by the California Green Building Standards Code. Policy 10.18.3 – Incorporate the provisions of the South Coast Air Quality Management District
Management Plans as conditions of approval for all
new development and re-development projects. Consistent. See discussion under Goal 10.18 above. In addition, the project would comply with applicable and required SCAQMD rules and regulations to minimize construction and operational emissions.

Goal 10.20 – Reduce criteria air pollutant emissions
through more efficient land use planning and
construction practices.

Consistent. See discussion under Goal 10.18 above. In addition, the project would increase the City housing stock and mix of housing while being adequately supported by transportation and utility infrastructure (see Section 4.N, Utilities and Service Systems, of this EIR) and public services (see Section 4.L, Public Services of this EIR). The project would also be consistent with the City’s land use goals and policies to develop low-density residential neighborhoods in areas on the City’s southern periphery that preserve the rural and open space character of their setting (see Section 4.I, Land Use and Planning, of this EIR). The project would also minimize air pollution by using of low-pollutant emitting interior finish materials for paints, carpet, vinyl flooring and particleboard, as required by the California Green Building Standards Code. Policy 10.20.4 – Continue to create local employment opportunities by maintaining an
adequate supply of designated commercial and
industrial land supply, in accordance with the Land
Use Element.

Not Applicable. The project is not a commercial or industrial development. The project would neither hinder nor conflict with implementation of this policy.

December 2015 4.B. Air Quality
Table 4.B-10 (Continued)
General Plan Consistency Analysis
City of Corona Skyline Heights Project PCR Services Corporation/SCH No. 2014021003 4.B-39 Goals and Policies Consistency
Policy 10.20.8 – Reduce particulate emission from
paved and unpaved roads, parking lots, and road
and building construction, as required by the South
Coast Air Quality Management District. Methods
include but are not limited to
Maintaining construction equipment engines in
good condition and in proper tune per
manufacturer’s specification for the duration of
construction
Turning off construction-related equipment,
including heavy-duty equipment, motor vehicles,
and portable equipment, when not in use for more
than five minutes
Encourage contractors to utilize alternative fuel
construction equipment (i.e., compressed natural
gas, liquid petroleum gas, and unleaded gasoline)
and low-emission diesel construction equipment
to the extent that the equipment is readily
available and cost effective
Using the electricity infrastructure surrounding
construction sites rather than electrical
generators powered by internal combustion
engines to the extent feasible
Implement dust control measures consistent with
South Coast Air Quality Management District Rule
403 – Fugitive Dust during the construction
phases of new project development
Apply water and/or approved nontoxic chemical
soil stabilizers according to manufacturer’s
specifications to all inactive construction areas
(previously graded areas that have been inactive
for 10 or more days).

Replacing ground cover in disturbed areas as
quickly as possible
Consistent. The proposed project would comply with applicable SCAQMD rules and regulations related to particulate emissions. Additionally, project-related emissions would not exceed the established regional and localized significance thresholds for particulate matter.

The project would implement measures to reduce on- and off-road construction emissions from heavy-duty diesel trucks and equipment by complying with anti-idling provisions for heavy-duty trucks, implementing fugitive dust control measures in accordance with SCAQMD Rule 403. Fugitive dust control measure consistent with Rule 403 include watering and/or use of soil stabilizers for disturbed areas and unpaved roads, the use of covers or sufficient freeboard space for haul trucks, replacing ground cover as soon as practicable, reducing vehicle speeds on unpaved roads to 15 miles per hour or less, and using clean paved roads where practicable. Implementation of these measure would minimize particulate emissions from paved and unpaved roads, parking lots, and road and building construction.

4.B. Air Quality December 2015
Table 4.B-17 (Continued)
General Plan Consistency Analysis
City of Corona Skyline Heights Project PCR Services Corporation/SCH No. 2014021003 4.B-40 Goals and Policies Consistency
Enclosing, covering, watering twice daily, or
applying approved chemical soil binders to
exposed piles with 5 percent or greater silt
content
Watering active grading sites at least twice daily
Suspending all excavating and grading operations
when wind speed (as instantaneous gusts) exceed
25 miles per hour over a 30-minute period.

Covering or maintaining at least two feet of
freeboard (i.e., minimum vertical distance
between top of the load and the top of the trailer),
in accordance with Section 23114 of the California
Vehicle Code, in all trucks hauling dirt, sand, soil,
or other loose materials
Sweeping streets adjacent to construction sites at
the end of the day
Installing wheel washers where vehicles enter and
exit unpaved roads onto paved roads, or wash off
trucks and any equipment leaving the site each
trip
Applying water three times daily or chemical soil
stabilizers according to manufacturers’
specifications to all unpaved parking or staging
areas or unpaved road surfaces
Posting and enforcing traffic speed limits of 15
miles per hour or less on all unpaved roads
Goal 10.21 – Reduce air quality degradation
through energy conservation.

Consistent. See discussion under Goal 10.18 above. In addition, the project would incorporate energy saving measures consistent with the California Green Building Standards Code. The project would reduce energy related to water use by installing water-conserving fixtures that would achieve at least a 20-percent reduction in indoor water use and moisture-sensing or other equivalent “smart” irrigation systems for larger landscaped areas. Common open space recreation areas would be planted with low-water plants that meet the California Department of Water Resources “Water Use Classifications of Landscape Species” (WUCOLS) low water use designation.

December 2015 4.B. Air Quality
Table 4.B-10 (Continued)
General Plan Consistency Analysis
City of Corona Skyline Heights Project PCR Services Corporation/SCH No. 2014021003 4.B-41 Goals and Policies Consistency
Policy 10.21.1 – Reduce the amount of energy
consumed by commercial and residential uses, as
recommended by the Southern California Air Quality
Management District. Consistent. See discussion under Goal 10.18 and Goal 10.21 above. Policy 10.21.2 – Continue to require the use and installation of energy conservation features in all
new construction projects and wherever feasible,
retrofitting in existing and re-development projects.

Consistent. See discussion under Goal 10.18 and Goal 10.21 above. Source: City of Corona General Plan; PCR Services Corporation, 2014

4.B. Air Quality December 2015
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City of Corona Skyline Heights Project
PCR Services Corporation/SCH No. 2014021003 4.C-1

4. ENVIRONMENTAL IMPACT ANALYSIS
C. BIOLOGICAL RESOURCES

INTRODUCTION
This section describes existing biological resources that occur or have the potential to occur on the project site or in the site vicinity. In addition, a description of applicable regulations is provided. The analysis evaluates the potential impacts to biological resources that could occur in association with implementation of the proposed project. The analysis in this section is based on reports prepared by Gonzales Environmental Consulting, LLC (GEC) and L&L Environmental, Inc. (L&L), which are provided in Appendix D of this Draft EIR and listed below:

Habitat Assessment & Rare Plant Survey for Special Status Plants (Sensitive Plant Report), August 1, 2013 (Revised April 23, 2014), prepared by GEC (GEC 2014a). Habitat Assessment & Focused Surveys for Burrowing Owl (Burrowing Owl Report), August 1, 2013 (Revised April 23, 2014), prepared by GEC (GEC 2014b). Habitat Assessment & Focused Surveys for Coastal California Gnatcatcher (California Gnatcatcher Report), August 1, 2013 (Revised April 23, 2014), prepared by GEC (GEC 2014c). Habitat Assessment & Focused Surveys for Least Bell’s Vireo (Least Bell’s Vireo Report), August 1, 2013 (Revised April 23, 2014), prepared by GEC (GEC 2014 d). Jurisdictional Delineation, August 1, 2013 (Revised April 23, 2014) prepared by GEC (GEC 2014e). This report was updated by L&L (see below).

Habitat Assessment Including the Results of a Focused Burrowing Owl Survey and MSHCP Consistency Analysis (MSHCP Consistency Analysis Report), August 1, 2013 (Revised April 23, 2014), prepared by GEC (GEC 2014f). Determination of Biologically Equivalent or Superior Preservation, August 1, 2013 (Revised April 23, 2014), prepared by GEC (GEC 2014g). This report was updated by L&L (see below).

A Biological Resources Assessment (BRA Report), March 2015, prepared by L&L (L&L 2015a). Jurisdictional Delineation (Jurisdictional Delineation Report), March 2015, prepared by L&L (L&L 2015b).

Determination of Biologically Equivalent or Superior Preservation of Riparian/Riverine Habitat (DBESP Report), March 2015, prepared by L&L (L&L 2015c).

1. ENVIRONMENTAL SETTING
a. Existing Conditions
The project site is located within the City of Corona sphere of influence in unincorporated Western Riverside County and is proposed to be annexed to the City during the entitlement process. The project site is comprised of 270.9 acres of vacant land (“project site”) situated in the hills to the southwest of the City of

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Corona, adjacent to the future alignment of the Foothill Parkway Westerly Extension. Within the project site boundary is an undeveloped 10-acre parcel which is considered “Not a Part” (NAP) and is owned by the U.S.

Forest Service. An additional 33-acres within the project site boundary will be graded by the Foothill Parkway project and the impacts have been considered in the Foothill Parkway documents; as such they are also excluded (i.e., NAP) from this analysis. Several properties, not part of the project described in this analysis, are part of the general plan amendment/annexation and as part of the process the City requested that technical reports address additional properties within the annexation boundary. While surveys of these areas occurred as a result of the general plan amendment/annexation study, no impacts are planned to these areas at this time and no impacts to these properties have been considered in this analysis. If development of these properties is planned in the future, additional studies and permits will be required. The 270.9-acre project site is located south of Wardlow Canyon Wash, west of the paved portion of Mabey Canyon Drive, west of Mangular Avenue, and north of the dirt road portion of Chase Drive. The Skyline Heights project is generally bounded to the north and east by single-family residences and on the south and west by the Cleveland National Forest and large privately owned parcels. The project site is an in-holding within the National Forest Service boundary. The project site consists of disturbed and undisturbed native habitat in the eastern foothills of the Santa Ana Mountains, in addition to ornamental areas dominated by non-native species. The site is characterized by relatively gentle to moderately sloping terrain in addition to steep topography. Several canyons and ravines are present that convey natural drainage across the project site.

Portions of the project site have been disturbed by anthropogenic disturbances (e.g., fire roads, illegal access, and adjacent land uses). Elevations of the project site range between approximately 955 above mean sea level in the northernmost point of the site within Wardlow Canyon Wash, to 1,700 above mean sea level at the western most boundary. There are several existing canyons and ravines that run across the project site. Three of the canyons are designated USGS blue line streams. Wardlow Wash (Feature 7) and Mabey Canyon Wash (Feature 6) are two of those blue lined streams and are located in the northern portion of the project site. The other blue line stream is un-named (referred to in this report as Feature 3, previously referred to as F-1 by GEC) and is located in the central portion of the project site. Another feature, referred to in this report as Feature 1 (previously referred to as D-2 by GEC), is a jurisdictional drainage in the southern portion of the project site.

Several other smaller non-jurisdictional tributaries also occur on-site.

The project site is within the Western Riverside Multiple Species Habitat Conservation Plan (WRC MSHCP), within Temescal Canyon Area Plan of the WRC MSHCP, as well as designated an MSHCP Burrowing Owl Survey Area.
(1) Vegetation Communities
The project site consists of several vegetation communities, characterized as Chaparral Alliance, Coast Live Oak Woodland Alliance, Eucalyptus/Pepper Alliance, Grassland Alliance, Mulefat Alliance, Sage Scrub Alliance, Sycamore Alliance, and Willow Alliance. The annexation area does not support Grassland Alliance, Sycamore Alliance, or Willow Alliance communities, but also supports a detention basin Mulefat Alliance, Sage Scrub Alliances, Chaparral Alliances, Eucalyptus/Pepper Alliance and disturbed, as shown in Figure

4.C-1, Habitat Map Including Annexation Area. Vegetation community mapping and classification is according to the California Native Plant Society (CNPS) Manual of California Vegetation (Sawyer, Keeler-Wolf and Evens 2009), California Natural Diversity Database (CNDDB) Natural Communities (CDFW 2013) and the CNPS Vegetation Alliances of Western Riverside County, California (Klein and Evens 2006). Acreages are

Habitat Map Including Annexa on Area FIGURE
Skyline Heights Project 4.C-1
Source: L & L Environmental, Inc., 2015. N

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summarized in Table 4.C-1, Vegetation Communities, below. A description of all these vegetation communities is provided below.

Riparian and Woodland Habitat
Woodlands are dominated by woody trees and tall scrub species forming a continuous canopy with an understory consisting of low shrubs and/or a variable grassy ground layer. Riparian areas include those transitional areas adjacent to rivers, streams, estuaries, lakes, and depressional wetlands that characteristically have a high water table and are subject to periodic flooding and influence from adjacent water bodies. The woodland plant communities observed in the study area include Quercus agrifolia Alliance (Coast Live Oak Woodland) and Platanus racemosa Alliance (California sycamore woodlands [also considered a riparian community). The riparian plant communities observed in the survey area include:

Baccharis salicifolia Alliance (Mulefat Scrub), Salix lasiolepis Alliance (Arroyo Willow thickets), and Platanus racemosa Alliance (California sycamore woodlands [considered both a woodland and riparian community).

Drainage features on the project site supporting riparian species include Features 1 (unnamed), 3 (unnamed), 6 (Mabey Canyon Wash), and 7 (Wardlow Wash); Features 2, 4 and 5 support upland habitats (see section (3) below for a description of the drainage features). The observed riparian and woodland habitats are described below.

Table 4.C-1
Vegetation Communities
Habitat
Existing Acreages in the Survey
Area
Existing Acreages in the Annexation
Area
Riparian and Woodland Habitats
Coast Live Oak Alliance 1.17 1.27
Mulefat Alliance 1.14 0.46
Sycamore Alliance 0.37 0
Willow Alliance 0.21 0
Subtotal 2.89 1.73
Upland Habitats
Chaparral Alliance 218.05 94.10
Grassland Alliance 5.54 0
Sage Scrub Alliance 41.59 16.79
Subtotal 265.18 110.89
Unvegetated/Altered Areas
Detention Basin 0 4.46
Disturbed 0 23.44
Eucalyptus/Pepper Alliance 2.82 0.18
Subtotal 2.82 28.08
Total Acreage 270.89 140.70
Source: PCR Services Corporation, 2015

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(a) Quercus agrifolia Alliance (Coast Live Oak () Woodland) 71.060.02 Coast live oak occurs as the dominant tree in the canopy. Poison oak is the dominant shrub in the understory. This Alliance occurs in the valley between the steep hills in the survey area (drainage Features F-1, F-3 and Mabel Canyon [F-6]). Quercus agrifolia is growing along and contributing to the riparian corridor as an intermittent canopy with a sparse ecotonal understory of riparian and Coastal Sage Scrub plant species: poison oak (Toxicodendron diversilobum), California Fuchsia (Epilobum canum), Douglas’ Nightshade (Solanum douglasii), an California buckwheat (Eriogonum fasciculatum). This community is very limited in the survey area.
(b) Platanus racemosa Alliance (California Sycamore Woodland) 61.310.00 In the survey area, this riparian community is composed primarily of sycamore (Platanus racemosa) and California sagebrush (Artemisia californica). This plant alliance has a global and state ranking of G3S3 (Global and State Vulnerable (rare; typically having 21 to 100 occurrences, or 3,001 to 10,000 individuals).

The community is very limited in the survey area, existing only in three small areas in drainage Feature F-3 and Mabey Canyon Wash (F-6).
(c) Salix lasiolepis Alliance (Arroyo Willow thickets) 61.201.01 In the survey area this riparian community is composed primarily of arroyo willow (Salix lasiolepis). This plant alliance has a global and state ranking of G4 S4 (Global and State Vulnerable (Apparently secure (uncommon but not rare, but with some cause for long-term concern; typically having 101 or more occurrences, or 10,001 or more individuals). This community is very limited in the survey area, existing only in limited areas of drainage Feature F-3. (d) Baccharis salicifolia Alliance (Mulefat thickets) 63.510.00 In the survey area this riparian community is strongly dominated by mulefat (Baccharis salicifolia). The plant alliance has a global and state ranking of G5 S4 (Global Vulnerable (Secure (common, widespread, abundant, and lacking major threats or long-term concerns) and State Vulnerable (Apparently secure (uncommon but not rare, but with some cause for long-term concern; typically having 101 or more occurrences, or 10,001 or more individuals). This community is very limited in the survey area, existing only in a narrow band along Mabey Canyon Wash (F-6) and Wardlow Canyon Wash (D-7) and occurs sporadically in drainage Feature F-3 but was not mapped because it occurs in areas of less than 0.1 acres.

Upland Habitats
Chaparral Alliances
Chaparral is a type of shrubland that is dominated by evergreen shrubs with small, thick, leathery, dark green, sclerophyllous leaves. The shrubs are relatively tall, dense and adapted to periodic wildfires and drought. Many typical Coastal Sage Scrub species also grow intermixed as associates with chaparral species.

Chaparral typically occurs on moderate to steep south-facing slopes with dry, rocky, shallow soils, becoming more abundant with higher elevations where temperatures are lower and moisture is higher. The chaparral vegetation communities observed in the survey area include Adenostoma fasciculatum Alliance (Chamise Chaparral) and Adenostoma fasciculatum-Eriogonum fasciculatum Alliance (Chamise-Buckwheat-Chaparral), as described below.

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(e) Adenostoma fasciculatum Alliance (Chamise Chaparral) 37.101.00 Adenostoma fasciculatum Alliance is dominated by the evergreen shrub, Adenostoma fasciculatum (Chamise), This Alliance forms an intermittent to continuous canopy less than three meters tall, growing over a sparse herbaceous layer, especially in older stands. Adenostoma fasciculatum is usually associated with all slope aspects, but is commonly found on the drier south- and west-facing slopes and ridges, growing in very shallow soils (mafic-derived). To be classified as Adenostoma fasciculatum Alliance, the stand must have at least 60% cover by A. fasciculatum (Sawyer, Keeler-Wolf and Evens 2009).

The shrub canopy associate species observed as important contributors to Adenostoma fasciculatum Alliance include: thickleaf Yerba Santa (Eriodictyon crassifolium), California buckwheat, Our Lord’s Candle (Hesperoyucca whipplei), toyon (Heteromeles arbutifolia), deerweed (Acmispon glaber), laurel sumac (Malosma laurina), and sugarbush (Rhus ovata). Several understory herbs listed below for Sage Scrub are expected as associates in Chaparral plant communities in the survey area. (f) Adenostoma fasciculatum-Eriogonum fasciculatum Alliance (Chamise-Buckwheat-Chaparral)

37.101.14
The Adenostoma fasciculatum-Eriogonum fasciculatum Alliance (Chamise-Buckwheat-Chaparral) 37.101.14 is also found in the survey area. In this community both species are consistently present in an open to intermittent shrub overstory, where Adenostoma fasciculatum is dominant or codominant with Eriogonum fasciculatum. Other species (e.g., Salvia mellifera, Arctostaphylos glauca, Encelia farinosa and Rhus ovata) often intermix in the shrub layer at low cover (Klein and Evens 2006).

Grassland Alliances
(g) Bromus Semi-natural Stands (California Annual Grassland) 42.026.00 California Annual Grassland consists of low herbaceous vegetation that is dominated by introduced annual grasses and is often associated with several native wildflower species, as well as introduced forbs. California Annual Grassland is typically dominated by annual grasses of various genera that are primarily of Mediterranean origin, including: Avena spp. (wild oats), Bromus spp. (bromes), and Hordeum spp. (barleys).

Species composition varies among stands, as the associate species may consist of several native herbs (or wildflowers). These wildflowers are important contributors to the ground layer, while emergent trees and shrubs may be present. Grasslands composed primarily of non-native species bromes (Bromus spp.), short- podded mustard (Hirschfeldia incana), filaree (Erodium spp.), Russian thistle (Salsola tragus), doveweed (Croton setigerus), and deerweed occur throughout the survey area. Showy annuals and perennials observed include: common fiddleneck (Amsinckia intermedia), small-flowered fiddleneck (Amsinckia menziesii), cryptantha (Cryptantha intermedia), and Fremont’s star lily (Toxicoscordion fremontii). No sensitive native grassland alliances were observed in the survey area. Native grasses were sparsely intermixed with dominate non-native species. Grasslands observed on site are dominated by non-native grass species:
slender wild Oat (Avena barbata), common wild oats (Avena fatua), ripgut grass (Bromus diandrus), soft chess (Bromus hordeaceus), and foxtail chess (Bromus madritensis ssp. rubens). California Annual Grassland also typically includes scattered nonnative forbs. Although California Annual Grassland is predominated by introduced annual grass species, this plant community has a significant

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component of native herbs and may provide some functional habitat for many wildlife species. Only when annual grassland is significantly influenced by invasive species (generally a result of a significant disturbance) is the plant community classified as Ruderal Grassland.

Sage Scrub Alliances
Sage Scrub is a shrubland dominated by facultative drought-deciduous, low growing, soft-leaved, and grayish-green (malacophyllus) shrubs and subshrubs. The plants typically exhibit a patchy distribution, often in close associated with chaparral habitats. The sage scrub alliances observed in the survey area include Eriogonum fasciculatum Alliance (California Buckwheat Scrub), Salvia leucophylla Alliance (Purple Sage Scrub), Salvia apiana Alliance (White Sage Scrub), and Salvia mellifera Alliance (Black Sage Scrub),, as described below. These communities generally occur on rolling hills at lower elevations in the survey area and outside the scour area of drainage Feature F-3. It then transitions into chaparral where hills become steep. Sage Scrub intermixes with chaparral throughout the survey area. (h) Eriogonum fasciculatum Alliance (California Buckwheat Scrub) 32.040.00 Eriogonum fasciculatum Alliance (California Buckwheat Scrub) is dominated by Eriogonum fasciculatum var. fasciculatum, which is a perennial shrub. One patch of Eriogonum fasciculatum Alliance, along the ridge top adjacent to a dirt road, is a monotypic stand of Eriogonum fasciculatum var. fasciculatum. This particular patch of Eriogonum fasciculatum Alliance most likely originated following construction of the fire road in the area. Some associate species to this plant community include Our Lord’s Candle and ripgut grass. (i) Salvia leucophylla Alliance (Purple Sage Scrub) 32.090.00 Salvia leucophylla Alliance (Purple Sage Scrub) is dominated by purple sage (Salvia leucophylla). This Alliance was observed as an important component of Sage Scrub within the survey area. Several associate native species contribute to the canopy of Salvia leucophylla Alliance onsite, including: California sagebrush, coyote bush (Baccharis pilularis), California bush sunflower (Encelia californica), California Buckwheat, slender wild oat, and black sage (Salvia mellifera).
(j) Salvia apiana Alliance (White Sage Scrub) 32.030.00 Salvia apiana Alliance (White Sage Scrub) is dominated by white sage (Salvia apiana), This Alliance exists when Salvia apiana is the sole, dominant, or important shrub growing with California sagebush in the canopy. Important shrub canopy contributors observed in the survey area include California sagebush and laurel sumac. Other herbaceous associate species observed growing below the low shrub canopy include slender wild oat, and short-pod mustard.
(k) Salvia mellifera Alliance (California brittle bush scrub) 32.020.00 In the Salvia mellifera Alliance, Salvia mellifera is usually the dominant shrub in the overstory. Eriogonum fasciculatum is consistently present, usually as a sub-dominant shrub. A variety of other coastal sage and chaparral species frequently intermix in the shrub layer as sub-dominants. This Alliance was observed as an important component of Sage Scrub within the survey area. Several associate native species contribute to the canopy of Salvia mellifera Alliance in the survey area, including: California sagebush, California bush sunflower, California buckwheat, slender wild oat, and purple sage.

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Unvegetated/Altered
(l) Eucalyptus Semi-natural stands (Eucalyptus groves) 79.100.00 Non-native landscape eucalyptus species (Eucalyptus spp.) are located immediately adjacent to drainage Feature F-3 and Mabey Canyon Wash (F-6). In the survey area, this community is integrated with Schinus spp. Semi-natural Stands (see below).
(m) Schinus spp. Semi-natural Stands (Pepper tree) 79.200.00 Non-native landscape pepper tree species (Schinus spp.) are located immediately adjacent to drainage Feature F-3 and Mabey Canyon Wash (F-6). In the survey area, this community is an intergrade with Eucalyptus Semi-natural Stands (see above).
(n) Riverine Habitat (streambed channels)
A streambed channel, either unvegetated or vegetated with upland species, generally qualifies as MSHCP riverine habitat. A channel is defined as a conduit that periodically or continuously contains moving water, or that forms a connecting link between two bodies of water. An intermittent subsystem of the riverine system exists where the channel contains nontidal flowing water for only part of the year. When flows are absent, surface water may be absent or water may remain in isolated pools. Riverine habitat occurs in a narrow band along the drainage features in the survey area where riparian habitats are absent. The riverine habitat onsite is largely unvegetated and contains recent fluvially deposited sediments.
(o) Road/Disturbed
Disturbed describes land or habitat that has been negatively altered, either by human activities (for building and road development purposes) or by natural causes (fires). As a result, this altered land is generally initially bare ground until either development occurs or natural succession begins. Habitat succession is a slow process of reestablishing original plant communities, but successional habitats are readily invaded by ruderal grass and forb species. Disturbed areas in the survey area are primarily existing dirt roads. Limited vegetation occurs in this land cover type and the species that are present tend to be weedy and invasive including species such as Centaurea melitensis, Sisymbrium irio, and Hirschfeldia incana. (p) Ornamental Ornamental vegetation occurs around Mabey Canyon Wash (F-6) near where an abandoned air strip is located, and along drainage Feature F-3 near Mangular Avenue. This vegetation type includes landscaped areas with planted species such as eucalyptus, pepper and pine trees (Pinus spp.). (2) Sensitive Biological Resources
The following discussion describes the plant communities within the project site and plant and wildlife species present, or potentially present, that have been afforded special recognition by Federal, State, or local resource conservation agencies and organizations.

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(a) Sensitive Plant Communities
The project site supports three plant communities which are considered California Natural Diversity Database (CNDDB) high inventory priority communities and are considered sensitive due to their decline in the region and/or their ability to support sensitive species. These include Platanus racemosa Alliance (California Sycamore Woodlands [CNDDB Code 61.310.00]), Salix lasiolepis Alliance (Arroyo willow thickets [CNDDB Code 61.201.01]), and Salvia apiana Alliance (White Sage Scrub [32.030.00]). (b) Sensitive Plant Species A list of sensitive plant species was created based on published literature and literature readily available on the internet, CNDDB records searches (for USGS Alberhill, Black Star Canyon, Corona North, Corona South, El Toro, Lake Mathews, Prado Dam, Riverside West and Santiago Peak 7.5’ minute topographic quadrangles [Rarefind 5 2013]), state and federal species lists, and habitat field surveys. The list of plants assessed for the project site includes 58 species of which eight (8) are listed as threatened, endangered, proposed, or candidates for listing as endangered or threatened, and 50 as sensitive species.

None of the eight (8) species listed as threatened, endangered, proposed, or candidates for these listings were observed in the survey area during multiple years of general surveys and a focused plant survey conducted in 2013. Following completion of the focused plant survey three (3) of these species were determined to have a low potential of occurrence in the survey area based on the presence of appropriate habitat although none were observed, including Braunton's milk-vetch (Astragalus brauntonii), San Diego ambrosia (Ambrosia pumila), and thread-leaved brodiaea (Brodiaea filifolia). San Diego ambrosia, and thread-leaved Brodiaea are covered species under the WRC MSHCP in areas outside the survey overlays for these species; the project is not within these survey overlays, specifically the Narrow Endemic Species and Criteria Area plant species survey overlays respectively. Braunton’s milkvetch is not a WRC MSHCP covered species. The remaining five (5) species were determined to have no potential of being present on the project site based on the lack or absence of appropriate habitat. Of the 50 sensitive plant species, one (1) was observed during the biological field surveys, Coulter’s matilija poppy (Romneya coulteri), and six (6) others were determined to have a potential to occur in the survey area based on the presence of suitable habitat, species range, and proximity to known occurrences. These species are: Catalina mariposa lily (Calochortus catalinae [high potential]), Fish’s milkwort (Polygala cornuta var. fishiae [moderate potential]), intermediate mariposa lily (Calochortus weedii var. intermedius [high potential]), intermediate monardella (Monardella hypoleuca ssp. intermedia [moderate potential]), white rabbit tobacco (Pseudognaphalium leucocephalum [moderate potential]), and chaparral nolina (Nolina cismontane [low potential]). None of these species were observed during field surveys conducted by GEC or L&L, although intermediate mariposa lily was reported from the northern project site in the CNDDB and in the August 2008 Foothill Parkway Westerly Extension DEIR (RBF Consulting 2008), and chaparral nolina was also recorded in the CNDDB as occurring within the northern end of the survey area. A total of 303 individuals of intermediate mariposa lily were observed in 30 locations during surveys conducted by BonTerra Consulting in May 2008; this species was not relocated in 2013 or observed elsewhere on the project site, although 2013 was considered a low rainfall year.

Intermediate mariposa lily is a covered species (Covered Species Adequately Conserved) under the WRC MSHCP.

Coulter's matilija poppy is a CDFW S4 (Apparently secure in California, but with some concern) and CNPS List 4.2 (watch list). This species is conditionally covered species under the WRC MSHCP and will be considered to be a when Covered Species Adequately Conserved the species-specific conservation objectives

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have been met.1 The distinctive perennial plant is found in sage scrub and chaparral. Blooming period is March-July. Fourteen populations of this species, with numerous subpopulations, were identified in 2008 and again in 2013 in the survey area. Results of the surveys in 2008 found 526 individuals. In 2013, only 236 plants were relocated. No new populations were identified. The 2008 survey year was considered a low-normal rainfall year, while 2013 was considered a low rainfall year. The types of microhabitats found for this species have sandy to coarse sandy substrates. The distribution of the plants was found in the high flow level of the active Feature 3, unnamed drainage, and on the fire (dirt) road in the middle of the survey area Figure 4.C-2, Coulter’s Matilija Poppy. A detailed discussion of each special status plant species, its status, habitat requirements, and the potential to occur within the project site are presented in the Sensitive Plant Report and the BRA Report (GEC 2014a and L&L 2015a). (c) Sensitive Wildlife Species
A list of special status wildlife species was created based on published literature and literature readily available on the internet, CNDDB records searches (for USGS Alberhill, Black Star Canyon, Corona North, Corona South, El Toro, Lake Mathews, Prado Dam, Riverside West and Santiago Peak 7.5’ minute topographic quadrangles [Rarefind 5 - 2013]), state and federal species lists, and habitat field surveys. The list of wildlife assessed for the project site includes 113 species of which 24 are listed as threatened, endangered, proposed, or candidates for listing as endangered or threatened, 72 as sensitive, and one (1) as a U.S. Forest Service sensitive species.

None of the 24 species listed as threatened, endangered, proposed, or candidates for these listings were observed in the survey area. Two of these species, coastal California gnatcatcher (Polioptila californica californica) and golden eagle (Aquila chrysaetos), have potentially suitable habitat in the survey area and were determined to have a moderate potential of occurring within the survey area. Focused surveys for the coastal California gnatcatcher were conducted in 2013 by GEC and the species was not observed. Based on these surveys it was determined coastal California gnatcatcher does not currently occupy the survey area.

The survey area does provide potentially suitable foraging habitat for the golden eagle. Both the coastal California gnatcatcher and the golden eagle are classified as Covered Species Adequately Conserved in the WRC MSHCP. Due to the presence of riparian habitat and the MSHCP Riparian/Riverine requirements (MSHCP Section 6.1.2), the least Bell’s vireo (Vireo bellii pusillus) was also analyzed in detail. The survey area is not located within critical habitat for least Bell’s vireo, and the vegetation does not appear to provide suitable territorial or breeding habitat for this species based on the diversity and density of the foliage.

Focused surveys were conducted and no least Bell’s vireo was observed in the survey area; it is unlikely the species would be expected in the survey area or in immediate adjacent areas. The survey area does not support suitable habitat for Stephens’ kangaroo rat and the area is not within the SKR HCP.

Of the 72 sensitive species, five were observed during the biological surveys: northern red-diamond rattlesnake (Crotalus ruber), Cooper’s hawk (Accipiter cooperii), California horned lark (Eremophila alpestris 1 As outlined in Table 9-3 of the WRC MSHCP, the Species Specific Conservation Objective for Coulter’s matilija poppy is as follows: “In order for this species to become a Covered Species Adequately Conserved, the following conservation must be demonstrated: Within the MSHCP Conservation Area, confirm 30 localities (locality in this sense is not smaller than one quarter section).”.

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actia), Lawrence’s goldfinch (Spinus lawrencei), and the San Diego black-tailed jackrabbit (Lepus californicus bennettii). Seventeen (17) other sensitive wildlife species were determined to have a high or moderate potential to occur in the survey area based on the presence of suitable habitat, species range and proximity to known occurrences. These species are; California silvery legless lizard (Anniella pulchra pulchra), orange- throated whiptail (Aspidoscelis hyperythra), coastal whiptail (Aspidoscelis tigris stejnegeri), rosy boa (Charina trivirgata), San Bernardino/San Diego ringneck snake (Diadophis punctatus ssp. modestus and similis), California mountain kingsnake (Lampropeltis zonata pulchra) San Diego population, coast horned lizard (Phrynosoma blainvillii), Coronado island skink (Plestiodon skiltonianus interparietalis), coast patch-nosed snake (Salvadora hexalepis virgultea), southern California rufous-crowned sparrow (Aimophila ruficeps canescens), burrowing owl (Athene cunicularia [see below]), black-chinned sparrow (Spizella atrogularis), pallid bat (Antrozous pallidus), Dulzura pocket mouse (Chaetodipus californicus femoralis), hoary bat (Lasiurus cinereus), San Diego desert woodrat (Neotoma lepida intermedia) and monarch butterfly (Danaus plexippus). Of these species the WRC MSHCP considers the following species “Covered Species Adequately Conserved”: orange throated whiptail, coastal whiptail, northern red-diamond rattlesnake, coast horned lizard, California horned lark, Cooper’s hawk, southern California rufous-crowned sparrow, San Diego desert woodrat and San Diego black-tailed jackrabbit. The California mountain kingsnake (San Diego population) will be considered “Adequately Conserved” once a Memorandum of Understanding is executed with the USFS that addresses management for this species on Forest Service Land. An additional one (1) species listed only by the U.S. Forest Service as sensitive, namely fringed myotis (Myotis thysanodes), was considered to have a low potential to occur within the study area.

Focused surveys were conducted for burrowing owl, one of the 17 sensitive wildlife species listed above, based on the presence of suitable habitat and burrows. However no signs of burrowing owls were observed at the burrows or adjacent to them, and no individuals of burrowing owl were located; thus this species does not currently occupy the study area.

A detailed discussion of each special status wildlife species, its status, habitat requirements, and the potential to occur within the project site are presented in the BRA Report (L&L 2015a) which is an updated to the MSHCP Consistency Analysis Report (GEC 2014f). The results of focused species surveys for burrowing owl, coastal California gnatcatcher, and least Bell's vireo are detailed in the Burrowing Owl Report, California Gnatcatcher Report, and Least Bell’s Vireo Report (GEC 2014b, 2014c, and 2014d). (3) Jurisdictional Features
The project site supports seven (7) main jurisdictional features (referred to as Features 1 through 7) with 56 tributaries, for a total of 63 features. Three of the main features are USGS mapped blue line streams, including Feature 3 (an un-named blue line stream), Feature 6 (Mabey Canyon Wash), and Feature 7 (Wardlow Wash) (Figure 4.C-3, Jurisdictional Feature Map). The features are all ephemeral in nature since water flow is not permanent or present seasonally for long periods.

A jurisdictional delineation was conducted by GEC (GEC 2014e) and updated by L&L, as detailed in the Jurisdictional Delineation (L&L 2015b). Based on the updated L&L delineation, the project site supports 2.16 acres of federal non-wetland jurisdictional area (“waters of the U.S.”) and 10.2 acres of state jurisdictional streambeds. Since the state jurisdictional streambeds incorporate riparian habitat these areas were also determined to meet the definition of MSHCP Riparian/Riverine Areas. Therefore, a total of 10.2 acres of

Coulter’s Ma FIGURE lija Poppy
Skyline Heights Project 4.C-2
Source: L & L Environmental, Inc., 2015. N

FIGURE Jurisdic onal Feature Map
Skyline Heights Project 4.C-3
Source: L & L Environmental, Inc., 2015. N

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MSHCP Section 6.1.2 Riparian/Riverine Areas were mapped within the project site. No wetlands were found within the project site.
(4) Wildlife Movement
Larger, relatively undisturbed areas of land play an increasingly critical role in connecting fragmented populations of plant and wildlife species. The basic framework of corridor analysis consists of identifying areas of habitat that are suitable to support regional wildlife movement. Habitat suitability depends upon the needs of a given species. It can be approximated by analyzing habitat characteristics, such as current vegetation, topography (e.g., aspect, slope, elevation), distance to water, and climatic variables (e.g., average temperature, precipitation). Because different wildlife species vary in their sensitivity to human disturbance, habitat suitability is constrained by disturbance variables, such as distance to roads, distance to towns, and traffic volumes. Generally, coverage of known distribution of a species (e.g., from sightings, radio-telemetry locations, hunter-kill and road-kill sites) is also developed. Finally, a probability contour is developed from the convergence of these coverages to indicate the likelihood of a given area being suitable for a given species. Where this probable habitat connects areas of known population centers, it is often termed a corridor. Species that utilize corridors may take several days to several generations to pass through a corridor. Passage species include large herbivores and medium to large carnivores that need corridors to allow individuals to pass directly between two areas. For these species, corridors facilitate juvenile dispersal, seasonal migration, and home range connectivity.

The project site is bordered by urban development to the north and east, and bordered by open space to the south and west. The project site is immediately north and east of MSHCP Core B (Cleveland National Forest).

The project site is not within any linkages identified by South Coast Missing Linkages (South Coast Wildlands 2008); however, the project site occurs along the foothills of the Santa Ana Mountains which was identified as the Corona-Temecula Foothills linkage in the South Coast Wildland’s 2001 Missing Linkages report (Penrod et al. 2001). The primary impediments to movement identified were gaps in habitat cover along the foothills of the Santa Ana Mountains due to urban development. The project site’s ability to facilitate wildlife movement was evaluated in relation to whether it provides links to seasonal foraging grounds or affects the exchange of genetic information between disjunct subpopulations. Portions of the project site are utilized for local movement by resident wildlife, primarily birds. Biological surveys of the project site did not detect bedding areas, or caves that could be used as dens for smaller and larger mammals. However, burrows and wildlife trails utilized by cottontails, ground squirrels, and coyotes were detected. In addition, human disturbances, such as runners, hikers with loose dogs, and mountain bikers, were observed on every survey occasion. Cats were also observed on each visit.

The project site includes native habitat that supports a variety of wildlife species and likely contributes generally to the Corona-Temecula Foothills linkage. However, it does not constitute a wildlife corridor (i.e., a piece of habitat, usually linear in nature, that connects two or more habitat patches that would otherwise be fragmented or isolated from one another), as movement on a regional scale is not confined within a specific corridor within this area. Rather, it is comprised of open space at the interface with urban development and is contiguous to a large expanse of open space within Core B and the Cleveland National Forest. Thus, wildlife currently move freely throughout the project site and surrounding areas via existing travel routes,2 2 A landscape feature (such as a ridgeline, drainage, canyon, or riparian strip) within a larger natural habitat area that is frequently used by wildlife to facilitate movement and provide access to necessary resources (e.g., water, food, cover, den sites). The travel route (Footnote continued on next page)

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such as drainages, ridgelines, and existing dirt roads. It should be noted that Wardlow Wash, which crosses the northernmost tip of the project site, was identified by BonTerra Consulting as a regional wildlife corridor that facilitates movement between the Cleveland National Forest and Prado Basin, as referenced by the Foothill Parkway Westerly Extension DEIR (RBF Consulting 2008). However, Wardlow Wash is relatively constrained by development on either side, road crossings at three locations (Paseo Grande, Serfas Club Drive, and Palisades Drive), and State Route 91 is a significant barrier to wildlife movement. A recognized connection between the Santa Ana Mountains and Chino Hills area is farther to the west via Coal Canyon (Penrod et al. 2001; Beier and Low 1992). The WRC MSHCP also proposes a connection between Existing Core A (Prado Basin/Santa Ana River) with Existing Core B (Cleveland National Forest) via Constrained Linkages 1 and 2, which are also farther to the west (but east of Coal Canyon). The project site also currently provides for movement on a smaller, local scale for species that live within the project site. b. Regulatory Framework
(1) Federal
(a) Endangered Species Act
The federal Endangered Species Act (ESA) protects plants and wildlife that are listed as endangered or threatened by the U.S. Fish and Wildlife Service (USFWS) and National Marine Fisheries Service (NMFS). ESA Section 9 prohibits the taking of endangered wildlife, where taking is defined as to “harass, harm, pursue, hunt, shoot, wound, kill, trap, capture, collect, or attempt to engage in such conduct” (50 Code of Federal Regulations [CFR] 17.3). For plants, this statute governs removing, possessing, maliciously damaging, or destroying any endangered plant on federal land, as well as removing, cutting, digging up, damaging, or destroying any endangered plant on non-federal land in knowing violation of state law. Under ESA Section 7, agencies are required to consult with the USFWS or NMFS if their actions, including permit approvals or funding, could adversely affect an endangered species (including plants) or its critical habitat. Through consultation and the issuance of a biological opinion, the USFWS or NMFS may issue an incidental take statement allowing take of the species that is incidental to another authorized activity, provided the action will not jeopardize the continued existence of the species. In cases where the federal agency determines its action may affect, but would be unlikely to adversely affect, a federally listed species, the agency informally consults with the USFWS and/or NMFS. This informal consultation typically involves incorporating measures intended to ensure effects would not be adverse. Concurrence from the USFWS and/or NMFS concludes the informal process. Without such concurrence, the federal agency formally consults to ensure full compliance with the ESA.
(b) Clean Water Act
The federal Water Pollution Control Act Amendments of 1972 (33 United States Code [USC] 1251–1376), as amended by the Water Quality Act of 1987, and better known as the federal Clean Water Act (CWA), is the major federal legislation governing water quality. The purpose of the federal CWA is to “restore and maintain the chemical, physical, and biological integrity of the nation’s waters.” Discharges into waters of the United States are regulated under CWA Section 404. Waters of the United States include: 1) all navigable waters (including all waters subject to the ebb and flow of the tide); 2) all interstate waters and wetlands; 3) is generally preferred because it provides the least amount of topographic resistance in moving from one area to another; it contains adequate food, water, and/or cover while moving between habitat areas, and provides a relatively direct link between target habitat areas.

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all other waters, such as intrastate lakes, rivers, streams (including intermittent streams), mudflats, sand flats, wetlands, sloughs, or natural ponds; 4) all impoundments of waters mentioned above; 5) all tributaries to waters mentioned above; 6) the territorial seas; and 7) all wetlands adjacent to waters mentioned above.

Important applicable sections of the CWA are discussed below:

Section 303 requires states to develop water quality standards for inland surface and ocean waters and submit to the U.S. Environmental Protection Agency (EPA) for approval. Under Section 303(d), the state is required to list waters that do not meet water quality standards and to develop action plans, called Total Maximum Daily Loads (TMDLs), to improve water quality.

Section 304 provides for water quality standards, criteria, and guidelines.

Section 401 requires an applicant for any federal permit that proposes an activity that may result in a discharge to waters of the United States to obtain certification from the state that the discharge will comply with other provisions of the CWA. Certification is provided by the respective Regional Water Quality Control Board (RWQCB). A Section 401 permit from the Santa Ana RWQCB would be required for the proposed project if a Section 404 permit were required.

Section 402 establishes the National Pollutant Discharge Elimination System (NPDES), a permitting system for the discharge of any pollutant (except for dredge or fill material) into waters of the United States. The NPDES program is administered by the RWQCB. Conformance with Section 402 is typically addressed in conjunction with water quality certification under Section 401.

Section 404 provides for issuance of dredge/fill permits by the United States Army Corps of Engineers (USACE; also referred to as ACoE in the supporting documents for the project). Permits typically include conditions to minimize impacts on water quality. Common conditions include: 1) USACE review and approval of sediment quality analysis before dredging, 2) a detailed pre- and post- construction monitoring plan that includes disposal site monitoring, and 3) requiring compensation for loss of waters of the United States. The areas of the project site that occur below mean higher high water (MHHW) would be subject to regulation under Section 404. (c) Migratory Bird Treaty Act
The Migratory Bird Treaty Act (MBTA) prohibits take of nearly all native birds. Under the MBTA, take means to kill, directly harm, or destroy individuals, eggs, or nests, or to otherwise cause failure of an ongoing nesting effort.
(2) State
(a) California Endangered Species Act
The California Endangered Species Act (CESA) authorizes the California Fish and Game Commission (Commission) to designate endangered, threatened, and rare species and to regulate the taking of these species (California Fish and Game Code [FGC] Sections 2050–2098). The CESA defines endangered species as those whose continued existence in California is jeopardized. State-listed threatened species are those not presently facing extinction, but that may become endangered in the foreseeable future. FGC Section 2080 prohibits the taking of state-listed plants and animals. The California Department of Fish and Wildlife (CDFW, formerly the Department of Fish and Game [CDFG] prior to January 1, 2013) also designates fully protected or protected species as those that may not be taken or possessed without a permit from the Commission and/or CDFW. Species designated as fully protected or protected may or may not be listed as

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endangered or threatened. When a species is both state- and federally listed, an expedited request for consistency with the USFWS biological opinion may be issued through a request for Section 2080.1 consistency determination.
(b) California Fish and Game Code
The California Fish and Game Code (FGC) is implemented by the Commission, as authorized by Article IV, Section 20, of the Constitution of the State of California. FGC Sections 3503, 3503.5, 3505, 3800, and 3801.6 protect all native birds, birds of prey, and nongame birds, including their eggs and nests, that are not already listed as fully protected and that occur naturally within the state. Section 3503.5 specifically states that it is unlawful to take, possess, or destroy any raptors (e.g., hawks, owls, eagles, and falcons), including their nests or eggs. The CDFW is the state agency that manages native fish, wildlife, plant species, and natural communities for their ecological value and their benefits to people.

Sections 1600-1616 of the FGC code allows the CDFW to issue Streambed Alteration Agreements for projects that will adversely affect wildlife habitat associated with any river, stream, or lake edges. Pursuant to this code CDFW asserts jurisdiction over the channel bed and banks, extending to the drip line of associated riparian vegetation if present.
(3) Regional
(a) Western Riverside County Multiple Species Habitat Conservation Plan The continued loss of habitat to new development and the cumbersome process of environmental review and habitat mitigation on a project-by-project basis led to adoption of the Western Riverside County Multiple Species Habitat Conservation Plan (WRC MSHCP) by Riverside County in 2003. The WRC MSHCP area encompasses an area stretching from the San Jacinto Mountains to the Orange County border. The WRC MSHCP is a multijurisdictional effort that provides a regional conservation solution to species and habitat issues that have historically threatened to stall infrastructure and land use development. The WRC MSHCP’s underlying goal is to protect multiple species by preserving a variety of habitat and providing linkages between different habitat areas and other undeveloped lands that would ensure long-term survival of 146 species of plants and animals. As long as adherence to the policies and requirements of the WRC MSHCP is maintained, participants in the WRC MSHCP, which include the County of Riverside and fourteen cities in western Riverside County (including the City of Corona), are allowed to authorize “incidental take" of plant and wildlife species of concern.
(b) Stephens’ Kangaroo Rat Long-Term Habitat Conservation Plan (SKR HCP) The USFWS issued a permit to the Riverside County Habitat Conservation Agency on May 3, 1996 to incidentally take the Stephens’ kangaroo rat (Dipodomys stephensi). This permit was not superseded by the WRC MSHCP; it is a separate HCP, specific to Stephen’s kangaroo rat. The 30-year Stephens’ Kangaroo Rat Habitat Conservation Plan (SKR HCP) is designed to acquire and permanently conserve, maintain, and fund the conservation, preservation, restoration, and enhancement of Stephens’ kangaroo rat occupied habitat.

The SKR HCP covers approximately 534,000 acres within the member jurisdictions (including the City of Corona), and includes an estimated 30,000 acres of occupied Stephens’ kangaroo rat habitat. The SKR HCP is within the WRC MSHCP. The SKR HCP requires members to preserve and manage 15,000 acres of occupied Stephens’ kangaroo rat habitat in seven Core Reserves encompassing over 41,000 acres. Currently 12,460 acres of occupied habitat exist within the Core Reserves. The WRC MSHCP considers the Stephens’ kangaroo

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rat as a Covered Species Adequately Conserved and affords protection to this species outside the boundaries of the SKR HCP.
(4) Local
(a) Corona General Plan
Chapter 5, Environmental Resources, of the City of Corona’s General Plan addresses several natural elements of the environment, including hydrological resources; biological resources; agricultural and mineral resources; air quality; and visual resources. The Environmental Resources Element provides an inventory of natural resources and a series of policies and programs deemed necessary by the City to use and protect those resources in a substantial manner. An analysis of project consistency with the applicable goals and policies of the Environmental Resources Element relating to biological resources is provided in the Analysis of Project Impacts subsection, below (see Threshold 5). (b) Corona Municipal Code
Section 17.70.070, Landscaping, of the Corona Municipal Code (CMC) addresses landscape requirements, including the use of water efficient landscaping. In addition, Chapter 12.22 of the CMC includes the Community Forestry Program, which describes requirements regarding the planning, planting, maintenance, alteration, and removal of all trees, shrubs, and landscape materials on public property. The CMC recognizes the benefits of landscaping, which include abatement of air and noise effects, reduction of soil erosion, and enhancement of the visual environment. The City of Corona Department of Water and Power implements the requirements of planting, maintenance, alteration, and removal of landscaping on public property.

2. ENVIRONMENTAL IMPACTS
a. Methodology
A Sensitive Plant Report, Burrowing Owl Report, California Gnatcatcher Report, Least Bell’s Vireo Report, Jurisdictional Delineation Report, MSHCP Consistency Analysis Report, and DBESP Report were prepared by GEC for the project (GEC 2014a through 2014g). A BRA Report, an updated Jurisdictional Delineation, and an updated DBESP of Riparian/Riverine Habitat were prepared by L&L (L&L 2015a through 2015c). The technical reports are contained in Appendix D of this Draft EIR. The methodology for the preparation of these reports included a literature review to evaluate the environmental setting and identify special-status species with potential to occur on site. The review included use of the California Natural Diversity Database (CNDDB [CDFW 2013) and the CNPS Inventory of Rare and Endangered Plants (CNPS 2013) for the USGS Alberhill, Black Star Canyon, Corona North, Corona South, El Toro, Lake Mathews, Prado Dam, Riverside West and Santiago Peak 7.5’ minute topographic quadrangles (USGS).

A series of biological surveys were conducted on the project site in 2005, 2006, 2008, and 2013. Aerial photography and digital vegetation maps were reviewed to determine potential community types within the project site. Preliminary ground-truthing surveys concurred with digital vegetation maps, and additional surveys were performed to accurately define the community types and boundaries. General wetland assessments of the project site were conducted in 2006, 2008, and 2013, which included general mapping of habitat(s) that may be subject to jurisdiction of the USACE pursuant to Section 404 of the CWA, CDFW pursuant to Sections 1600-1612 of the California Fish and Game Code, and WRC MSHCP Section 6.1.2. An updated delineation was conducted in 2015. General reconnaissance and habitat assessment surveys were

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completed to determine habitat suitability for listed species and special status plant, wildlife, and aquatic species. Sensitive plant surveys of the project site were conducted in 2005, 2006, 2008, and 2013. Focused species-specific surveys were conducted for burrowing owl, coastal California gnatcatcher, and least Bell’s vireo in 2013.
b. Thresholds of Significance
Appendix G of the CEQA Guidelines (the Initial Study Environmental Checklist form) and the City’s Initial Study Checklist include questions relating to biological resources that are utilized as the thresholds of significance in this section (Thresholds 1-6). Accordingly, the proposed project may create a significant environmental impact if it would result in one or more of the following:

Threshold 1: Have a substantial adverse effect, either directly or through habitat modifications, on any species identified as a candidate, sensitive, or special status species in local or regional plans, policies, or regulations, or by the California Department of Fish and Game or U.S. Fish and Wildlife Service (refer to Impact Statement 4.C-1);
Threshold 2: Have a substantial adverse effect on any riparian habitat or other sensitive natural community identified in local or regional plans, policies, regulations or by the California Department of Fish and Game or U.S. Fish and Wildlife Service (refer to Impact Statement 4.C- 2); Threshold 3: Have a substantial adverse effect on federally protected wetlands as defined by Section 404 of the Clean Water Act (including, but not limited to, marsh, vernal pool, coastal, etc.) through direct removal, filling, hydrological interruption, or other means (refer to Impact Statement

4.C-3);
Threshold 4: Interfere substantially with the movement of any native resident or migratory fish or wildlife species or with established native resident or migratory wildlife corridors, or impede the use of native wildlife nursery sites (refer to Impact Statement 4.C-4); Threshold 5: Conflict with any local policies or ordinances protecting biological resources, such as a tree preservation policy or ordinance (refer to Impact Statement 4.C-5); or Threshold 6: Conflict with the provisions of an adopted Habitat Conservation Plan, Natural Community Conservation Plan, or other approved local, regional, or state habitat conservation plan (refer to Impact Statement 4.C-6).
c. Project Design Features
Project Design Features (PDFs) have been incorporated as part of the project to address potential indirect effects as result of the urban/wildlands interface, as required by the WRC MSHCP (see also Impact 4.C-6, section (5), of this section). These PDFs include the following:

PDF BIO-1, Drainage – The project incorporates project streets, open channels and natural drainage courses as well as a comprehensive system of underground storm drains to handle storm

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runoff from the project site. Storm water from the project site and off-site areas will be directed to storm drains. The design and operation of the drainage channel shall be adequate to preclude discharge of water into open space areas that are of lower quality or higher quality than current conditions. The proposed development shall incorporate measures, including measures required through the NPDES requirements, to ensure that the quantity and quality of runoff discharged to the open space area is not altered in an adverse way when compared with existing conditions. In particular, measures shall be put in place to avoid discharge of untreated surface runoff from developed and paved areas into open space areas. Stormwater systems shall be designed to prevent the release of toxins, chemicals, petroleum products, exotic plant materials, or other elements that might degrade or harm biological resources or ecosystem processes within open space areas. This will be accomplished using a variety of methods including natural detention basins, grass swales, or mechanical trapping devices. Regular maintenance shall occur to ensure effective operations of runoff control systems.

PDF BIO-2, Toxics – The proposed project is designed to utilize natural drainage patterns for the flow of surface water. Water Quality Best Management Practices (BMPs) include education, storm drain stenciling, and street sweeping in compliance with the City of Corona’s requirements. The earthen channel shall be signed to filter potential toxics in the storm water prior to its discharge into open space areas. These BMPs will be implemented as part of the storm water pollution prevention measures for the project, in accordance with all appropriate NPDES requirements. The project would result in the additional use of hazardous materials in limited quantities associated with normal residential use such as cleaning products, solvents, herbicides, and insecticides.

However, compliance with regulations will reduce the potential risk of hazardous material exposure to a level that is less than significant. An information pamphlet has been prepared for each homeowner regarding the use of toxics.

PDF BIO-3, Lighting – Outdoor lighting of residences will be designed so that all direct beams would be confined to dwelling sites. Project lighting will not intrude into the open space conservation areas. Street lighting, parking lot lighting, and other project-related illumination sources will be positioned, directed, and shielded so as to avoid “light spill” into the conserved areas. The proposed project will avoid any night lighting adjacent to the open space areas. Night lighting will not be used during the course of construction unless absolutely necessary. If necessary, the lights will be directed and shielded to minimize lighting of the surrounding habitat. The level of off-site lighting and lighting fixtures would comply with the applicable requirements and policies of the City of Corona.

PDF BIO-4, Noise – The proposed project incorporates landscape elements including trees, shrubs, and groundcover, which will assist in noise reduction on the project site. In addition, a noise analysis prepared for the project found that no proposed on-site or surrounding sensitive land uses would experience long-term noise levels in excess of 65 dBA during the daytime hours under build-out of the proposed project. This daytime noise level would not result in exterior nighttime levels greater than 45 dBA. Therefore, no noise created on the project site would exceed residential noise standards.

PDF BIO-5, Invasives – Exotic Vegetation Control – Design guidelines for the project will provide the homeowners with a list of native landscaping materials permitted within the project site.

These materials have been selected for their contribution to the project theme,

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adaptability to local climatic and soil conditions, and for their compatibility with the unique natural environment in the project site. The WRC MSHCP has identified exotic invasive plants that should be areas avoided adjacent to the MSHCP Conservation Area in Table 6-2, Section 6.1.4 of the WRC MSHCP; none of these plants will be utilized for the proposed project and their use by future homeowners will be prohibited.

PDF BIO-6, Barriers – The proposed project will include theme walls along project perimeter streets adjacent to public streets, and will include walls and fencing located where public view and/or important interfaces are of concern. The proposed project will incorporate special edge treatments designed to separate development areas from open space areas.

These areas of native landscaping and fencing will serve to minimize unauthorized public access, domestic animals predation, and illegal trespass and dumping. Exclusion fencing will be permanently placed where development abuts avoided and adjacent open space areas. The exclusion fence will be a minimum of eight feet in height and will be installed and maintained for the purposed of controlling human and pet access (cats and dogs) into the open space area and be in compliance with WRC MSHCP requirements. The fencing will be permanent and will be maintained in perpetuity. Approval of the fencing design will be required by the City of Corona prior to project initiation.

PDF BIO-7, Access – Access points between native habitats and the project development will be posted with signage requesting residents to stay on the trails and not to disturb habitat.

Yard fencing with no back gate will reduce access to native habitats adjacent to the project.

PDF BIO-8, Pets – Uncontrolled pets, feral dogs and cats can predate on native wildlife species.

Appropriate signage will be posted requesting residents leash their pets. Homeowner Educational pamphlets will be used to inform them of the potential impacts by uncontrolled pets on native habitats and to request residents be good stewards of the land and prevent or limit their domestic cats from being allowed to openly hunt in the avoidance area.

PDF BIO-9, Grading/Land Development – All manufactured slopes associated with site development will be within the project site and there will be no impact to the MSHCP Conservation Area. All manufactured slopes that abut the natural open space will be retained as open space buffer zones. All manufactured slopes and areas disturbed by construction of these slopes will be revegetated with appropriate non-invasive buffer species during project construction.

It is anticipated that these PDFs will be incorporated in the project conditions of approval. No other PDFs have been identified for the project specifically related to biological resources. However, as also indicated in Section 2, Project Description, of this Draft EIR, open space would be provided within the project site in the form of landscaped slopes, landscaped and native open space areas, and landscaped detention basins.

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d. Analysis of Project Impacts
(1) Sensitive Species
Threshold 1: Have a substantial adverse effect, either directly or through habitat modifications, on any species identified as a candidate, sensitive, or special status species in local or regional plans, policies, or regulations, or by the California Department of Fish and Game or U.S. Fish and Wildlife Service?
Impact 4.C-1 The project site has been reported in CNDDB to support intermediate mariposa lily (in 30 locations) and chaparral Nolina (within a small portion of the project site), and was observed to support Coulter’s matilija poppy. Since the intermediate mariposa lily and chaparral nolina species were not relocated during surveys conducted by GEC, no significant impacts to these species are anticipated. Nevertheless, intermediate mariposa lily is a covered species under the WRC MSHCP and payment of the MSHCP Development Fee would reduce impacts to less than significant. Chaparral nolina is not covered under the WRC MSHCP but was only recorded within a small portion of the project site; the record in CNDDB occurs over a large area outside of the project site. As such, any impacts would be considered adverse but not significant and would not require mitigation. Coulter’s matilija poppy is conditionally covered under the WRC MSHCP and the project would impact approximately 40 percent of the identified population. Impacts would be considered adverse but not significant due to the large distribution and number of locations of this species. Furthermore, mitigation measures proposed for the project would also benefit avoided populations of Coulter’s matilija poppy by minimizing direct and indirect impacts, including Mitigation Measures BIO-1, BIO-4, and BIO-5, in addition to Project Design Features PDF BIO-1 through PDF BIO-9 to address edge effects pursuant to WRC MSHCP requirements for urban/wildlands interface. These measures would also reduce potential impacts to unobserved or new growth of sensitive species identified as having a moderate or high potential of occurring in the survey area. Focused surveys conducted for burrowing owl and least Bell’s vireo were negative. Mitigation Measures BIO-2 and BIO-3 are proposed to ensure no future impacts will occur to migratory and nesting birds and burrowing owl, respectively, prior to construction.

With the implementation of the proposed mitigation measures, which would provide protection to the special-status species if they are found on the project site, impacts would be reduced to a less than significant level. Mitigation measures are also proposed to address indirect impacts. (a) Sensitive Plant Species
Implementation of the proposed project would result in the direct removal of numerous common plant species, both native and non-native, within the project site. A list of plant species observed within the project site is included in Appendix A of the BRA Report (included in Appendix D in this Draft EIR). Common plant species present within the project site occur in large numbers throughout the region and their removal does not meet the significance thresholds defined above. Therefore, impacts to common plant species would be considered a less than significant impact and no mitigation is required.

As indicated in the Environmental Setting section, above, Coulter’s matilija poppy was observed within the project site. Coulter's matilija poppy is a CNPS Rank 4.2 species (Rank 4: Plants of limited distribution – Watch list; 0.2: Fairly endangered in California [20-80% occurrences threatened]). Approximately 526 plants were recorded in 2008 and 236 plants were recorded in 2013. Coulter's matilija poppy is a

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conditionally covered species under the WRC MSHCP; this species will be considered to be a Covered Species Adequately Conserved when the species-specific conservation objectives have been met. Due to the large distribution and number of locations of this species, impacts would be considered adverse but not significant. Impacts are proposed to approximately 40 percent of the identified population (between 95 and 211 individuals based on the 2013 versus 2008 observations of 236 and 526 individuals, respectively); the remaining approximate 60 percent would be avoided within 117.39 acres of natural habitat. Mitigation Measures proposed for the project would avoid impacts to avoided Coulter’s matilija poppy plants, including Mitigation Measures BIO-1, BIO-4, and BIO-5. BIO-1 would require flagging or fencing of impact and avoidance areas prior to clearing to prevent encroachment into avoided areas, periodic monitoring by a qualified biologist during clearing of habitat as determined appropriate, and implementation of Best Management Practices (BMPs) to prevent impacts to avoided biological resources. Mitigation Measures BIO4 and BIO-5 would require measures to minimize the introduction of invasive species. In addition, Mitigation Measure BIO-12 requires mitigation for impacts to Riparian/Riverine Areas, and could include planting of species such as Coulter’s matilija poppy if appropriate and/or feasible. Also PDFs are proposed to include measures to minimize effects from the urban/wildlands interface including human and pet encroachment and invasive species pursuant to the WRC MSHCP requirements. These mitigation measures and PDFs would also minimize potential impacts to unobserved or new growth of sensitive species identified as having a moderate or high potential of occurring in the survey area, but not previously observed.

Intermediate mariposa lily was reported from the northern project site in the August 2008 Foothill Parkway Westerly Extension DEIR. Intermediate mariposa lily is a CNPS Rank 1B.2 species (Rank 1: Rare, threatened, or endangered throughout their range; 0.2: Fairly endangered in California [20-80% occurrences threatened]). A total of 303 individuals were observed in 30 locations during surveys conducted by BonTerra Consulting in May 2008; these locations are proposed for impacts although the species was not relocated during the 2013 survey. As this species was not observed during current surveys, the impacts are unknown but can be estimated at less than 100 individuals. Intermediate mariposa lily is a covered species under the WRC MSHCP. Thus, payment of the MSHCP Development Fee would reduce impacts to less than significant. Chaparral nolina is not a covered species under the WRC MSHCP. This species was recorded in CNDDB as occurring over a large area that crossed only a small portion of the project area. As this species was not observed or previously detailed on the project site the impacts are unknown and cannot be clearly quantified. However, based on the large distribution of the recorded population and the small portion of the project site included in the CNDDB occurrence, impacts from the project would be considered adverse but not significant and no mitigation is required.

Of the remaining four species with potential to occur in the survey area, Catalina mariposa lily, Fish’s milkwort, intermediate monardella, and white rabbit tobacco, only Fish’s milkwort is a covered species under the WRC MSHCP Fish’s milkwort will be considered a “Covered Species Adequately Conserved” once preservation levels within the Conservation Areas are met. However, as the species were not observed over several years, if impacts occur they are expected to be limited. Impacts to these species are considered less than significant and no mitigation is required. The remainder of those sensitive plant species that were documented as occurring within the region are not expected to occur within the project site due to the lack of suitable habitat, the project site being outside of the known distribution or elevation range for the species, or due to negative results of multiple years of

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focused surveys. Therefore, no impacts would occur to these sensitive plant species with implementation of the proposed project, and no mitigation is required.
(b) Sensitive Wildlife Species
As indicated in the Environmental Setting section, above, the majority of the wildlife species that were observed during surveys on-site are considered common to the region. Five (5) sensitive species were observed within the survey area, including northern red-diamond rattlesnake, Cooper’s hawk, California horned lark, Lawrence’s goldfinch, and San Diego black-tailed jackrabbit. All these species with the exception of Lawrence’s goldfinch, are Covered Species Adequately Conserved in the WRC MSHCP. Payment of the MSHCP Development Fee would reduce impacts of WRC MSHCP covered species to less than significant. For species not covered under the WRC MSHCP, the project was designed to avoid 117.39 acres of natural habitat which will limit potential impacts to sensitive species in the survey area. In addition, Mitigation Measure BIO-2 requires avoiding clearing and grubbing of habitat during the birds nesting season, which will reduce impacts to less than significant if bird species present at the time of construction.

No threatened or endangered species were recorded or observed in the survey area, although four (4) species were considered including golden eagle, coastal California gnatcatcher, least Bell’s vireo, and the Stephens’ kangaroo rat. The golden eagle was considered to have a potential to occur for foraging only, but was not observed during any of the general or focused surveys conducted within the survey area. Focused surveys for coastal California gnatcatcher and least Bell’s vireo were also negative. For Stephens’ kangaroo rat it was determined no suitable habitat occurs within the survey area, and the site is not within the SKR HCP. None of these species have been previously recorded on the project site. With the exception of the least Bell’s vireo which is conditionally covered (requiring “Additional Survey Needs”, the remaining three species are Covered Species Adequately Conserved in the WRC MSHCP. Payment of the MSHCP Development Fee would reduce impacts of WRC MSHCP covered species to less than significant. For species not covered under the WRC MSHCP, the project was designed to avoid 117.39 acres of natural habitat which will limit potential impacts to sensitive species in the survey area. In addition, Mitigation Measure BIO-2 requires avoiding clearing and grubbing of habitat during the nesting season, which will reduce impacts to less than significant if bird species are present at the time of construction.

Seventeen (17) other sensitive wildlife species were determined to have a high or moderate potential to occur in the survey area based on the presence of suitable habitat, species range and proximity to known occurrences. Of these, five species are Covered Species Adequately Conserved in the WRC MSHCP, including orange throated whiptail, coastal whiptail, coast horned lizard, southern California rufous-crowned sparrow, and San Diego desert woodrat. The California mountain kingsnake (San Diego population) will be considered “Adequately Conserved” once a Memorandum of Understanding is executed with the USFS that addresses management for this species on Forest Service Land. Payment of the MSHCP Development Fee would reduce impacts of WRC MSHCP covered species to less than significant.

The burrowing owl is a species that requires “Additional Survey Needs” pursuant to the WRC MSHCP in mapped areas identified as the survey area overlays. The project site is located within the required survey area and focused surveys were conducted. No burrowing owl or sign of burrowing owl were observed in the survey area. Although the site is currently not occupied, this species is migratory and has the potential to occupy the site in the future. Mitigation Measure BIO-3 requires a pre-construction survey for burrowing

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owls to prevent impacts to this species, and mitigation should owls be observed pursuant to CDFW guidelines (CDFW, 2012). With this mitigation measure impacts are considered less than significant.

The remaining ten (10) species are not covered under the WRC MSHCP, including the California silvery legless lizard, rosy boa, San Bernardino/San Diego ringneck snake, California mountain kingsnake, Coronado island skink, coast patch-nosed snake, black-chinned sparrow, pallid bat, Dulzura pocket mouse, hoary bat, and monarch butterfly.

Direct Impacts: Each of the sensitive species discussed above that are known to occur or have a high to moderate potential to occur in the habitat on or immediately adjacent to the proposed impact area, have a potential to be directly impacted during construction of the project if they are present at the time of construction. The noise, activity, and presence of humans on the worksite will likely discourage many species of wildlife from the site during working hours, depending on the mobility of the species. More mobile species will move away from active construction zones into adjacent habitats. Wildlife may take refuge around the equipment in off hours and, if present, could be injured or killed by construction vehicles or passenger vehicles when vehicles are first started/moved, when species are moving through the construction zones, or when hiding within the impact area.

The larger mammal and bat species are not expected to be directly impacted and were considered to have a low potential of impacts, based on their high mobility levels and lack of roosting habitat observed. It is possible, though, that potential roosting or denning habitat does occur in the project impact area or that burrows went unobserved. In addition, the possibility cannot be completely eliminated that these species could be hit by construction vehicles or trapped in a roost/den location. Take of these species is possible; however, the wide territories of these species, vast open habitat in the area, no existing access restrictions around the project area preventing escape, and the nocturnal habits of some species reduce the potential for impacts.

Avian species have a low-moderate potential of being directly impacted based on their mobility and the relatively slow moving construction equipment, but if active nests are present within the project area, eggs and juveniles have a high potential of being impacted.

Small mammal and reptile species have a higher potential to be impacted by construction activities. Small mammals and reptiles can be very mobile, but often hide or rest in subsurface burrows or in debris piles and could be impacted during clearing, grubbing, dirt moving or construction. During construction the noise, activity, and presence of humans on the worksite will likely discourage mammals from the site during working hours, but these species may take refuge around the equipment or in subsurface burrows and debris piles in off hours.

Sensitive reptile and small mammal species that have moderate or high potential for occurring within the habitat in the survey area are considered to have a moderate potential of being directly impacted.

Mitigation Measures have been incorporated to minimize direct impacts to sensitive wildlife species.

Mitigation Measure BIO-1: flagging or fencing the impact area to prevent unintended impacts, biological monitoring, and BMPs to avoid inadvertent impacts to avoided biological resources. BMPs include placing refuse in covered containers and removing daily so as to reduce the potential for attracting wildlife to an

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unsafe construction zone where they may be trapped or injured. This will also reduce opportunistic predatory wildlife such as crows, ravens, coyotes, dogs etc.; Mitigation Measure BIO-2: avoiding clearing and grubbing between January 1 and September 1 or conducting a nesting bird clearance will reduce the impacts to nesting birds, eggs or dependent juveniles during construction, although intended to minimize impacts to nesting birds avoidance of this period (if possible) would also reduce impacts to other breeding species; Mitigation Measure BIO-3: preconstruction survey for burrowing owls and mitigation, if observed. The species that are not ‘Adequately Conserved’ under the WRC MSHCP, California silvery legless lizard, rosy boa, San Bernardino/San Diego ringneck snake, Coronado island skink, coast patch-nosed snake, black- chinned sparrow, pallid bat, Dulzura pocket mouse, hoary bat and monarch butterfly are considered sensitive by the CDFW and/or USFS and are being monitored for changes in their level of rarity. At this time impacts to these species are generally not regulated and with the mitigation measures outlined, impacts are considered to be less than significant.

Indirect Effects: Habitat fragmentation will consist of the loss of 153.5 acres of native habitats and isolation of native habitats to the east of the project from the larger Core B habitat area. The Project will incorporate barriers to prevent both common and sensitive wildlife species from entering the residential development and increasing their potential for impact by humans, vehicles, pets or other urban hazards. The barriers would also prevent human and pet encroachment and the potential for direct impacts by those means.

These preventative measures, while incorporated for the safety of the wildlife and adjacent habitat, also restricts wildlife movement and adds to habitat fragmentation.

Amphibian, reptile, avian, mammal and insect species may experience indirect impacts from construction including, increases in noise, chemical emissions, and vibration impacts resulting in avoidance and abandonment of the area. Movement of species could concentrate populations, increase competition for resources in adjacent habitats and leave displaced individuals vulnerable to predation. Those species that may use the project area for foraging will still have access to large expanses of relatively undisturbed habitat in the project vicinity, including the Cleveland National Forest lands to the west. Due to the remote location and open area emissions should disperse.

Although the species will be displaced and may alter behavior, Mitigation Measure BIO-2 which recommends clearing and grubbing be conducted outside the nesting bird season, or, if work cannot be avoided, nesting bird surveys be conducted prior to impacts, will prevent impacts to eggs and juveniles. If avoidance is possible it will also reduce impacts to all wildlife during typical reproduction periods. With the presence of substantial habitat of equal quality nearby, the project vicinity can provide sufficient foraging and nesting habitat. In addition, the WRC MSHCP considers the development throughout the County and balances development with conservation of the highest quality and largest possible areas of native habitats. The WRC MSHCP does not identify the survey area as a Conservation Area.

Increases in invasive plant species could affect the diet of small herbivorous mammal species by displacing their primary food sources and out-compete native vegetation that may be needed by specific wildlife species (i.e. host plants). A potential increase in invasive species would likely occur along the perimeter of the impact area, where newly exposed soils could provide fertile ground. Invasive species that may occur along the current roadway and within the impact area could disperse seed to newly turned soil. Large areas of undisturbed vegetation occur in the project vicinity and would be available food sources for these species.

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Mitigation Measures BIO-4 and BIO-5 are incorporated to minimize increases in invasive vegetation; measures to avoid invasive vegetation impacts are also proposed as PDFs in compliance with WRC MSHCP requirements. After completion of construction, noise levels adjacent to the site will be increased over current conditions at those locations, but are not expected to exceed residential noise standards. In addition, barriers are proposed between residential development and conservation areas, which will reduce the amount of noise, chemical emissions and fugitive dust from the development crossing into or affecting wildlife in the conservation areas after completion of construction.
(2) Riparian Habitat
Threshold 2: Have a substantial adverse effect on any riparian habitat or other sensitive natural community identified in local or regional plans, policies, regulations or by the California Department of Fish and Game or U.S. Fish and Wildlife Service? Impact 4.C-2 Implementation of the proposed project would result in significant impacts to four riparian habitat alliances and a sensitive natural sage scrub community. However, implementation of the prescribed mitigation measure would reduce potentially significant impacts to a less than significant level.

Impacts to plant communities are summarized in Table 4.C-2, Direct Impacts to Vegetation Communities, below. The project site supports five (5) plant communities that are considered sensitive natural communities by the CNDDB and/or protected pursuant to the WRC MSHCP. These include the four (4) riparian vegetation alliances, and one of the sage scrub alliances. Specifically, all four riparian vegetation alliances totaling 2.89 acres (including Coast Live Oak Alliance, Mulefat Alliance, Sycamore Alliance, and Willow Alliance) meet the WRC MSHCP definition or Riparian/Riverine Areas and require compensatory mitigation for impacts. Three (3) communities are considered sensitive (high priority for inventory) by CNDDB, including 0.37 acre of Sycamore Alliance (Platanus racemosa [California sycamore woodlands] Alliance), 0.21 acre of Willow Alliance (Salix lasiolepis [Arroyo willow thickets] Alliance), and one of the four Sage Scrub Alliances, specifically Salvia apiana (White sage scrub) Alliance.

Impacts will occur to 0.72-acre of riparian habitat that meets the definition of MSHCP Riparian/Riverine Areas (25 percent of the total 2.89 acres); the majority of impacts will occur to the Sycamore and Willow Alliances (0.32 acre and 0.21 acre, respectively) that are also considered of high priority for inventory by CNDDB. Although impacts will occur to the Sage Scrub Alliance, the specific acreage to the CNDDB sensitive Salvia apiana Alliance is unknown. However, since the project site is not within any MSHCP Criteria Cells requiring conservation of habitats, impacts to this vegetation community is considered covered under the WRC MSHCP. The impacts to all vegetation communities within the survey area are depicted on Figure 4.C-4, Habitat Impacts. Implementation of Mitigation Measure BIO-12 would compensate for impacts to riparian habitats and reduce impacts to a less than significant level. This mitigation is also intended to satisfy compensatory requirements for regulatory permitting outlined in Mitigation Measures BIO-6 through BIO-9. Since impacts

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to the CNDDB sensitive Salvia apiana Alliance is considered covered under the WRC MSHCP, payment of the MSHCP mitigation fee would reduce impacts to this community to a less than significant level.

Indirect impacts to avoided plant communities could also occur through dust generated during construction, a potential increase in non-native species, and human and pet encroachment. With implementation of Mitigation Measures BIO-4 and BIO-5, and PDFs intended to address edge effects from the development, potential indirect impacts would be reduced to a less than significant level. (3) Wetlands Threshold 3: Have a substantial adverse effect on federally protected wetlands as defined by Section 404 of the Clean Water Act (including, but not limited to, marsh, vernal pool, coastal, etc.) through direct removal, filling, hydrological interruption, or other means? Table 4.C-2
Direct Impacts to Vegetation Communities
Habitat
Existing in the Survey
Area (acres) Avoided (acres)
Project impacts
(acres)
Riparian and Woodland Habitats
Coast Live Oak Alliancea 1.17 1.07 0.1
Mulefat Alliancea 1.14 1.05 0.09
Sycamore Alliancea,b 0.37 0.05 0.32
Willow Alliancea, b 0.21 0 0.21
Subtotal 2.89 2.17 0.72
Upland Habitats
Chaparral Alliance 218.05 93.66 124.39
Grassland Alliance 5.54 2.12 3.42
Sage Scrub Alliance b,c 41.59 16.62 24.97
Subtotal 265.18 112.40 152.78
Unvegetated/Altered Areas
Detention Basin 0 0 0
Disturbed 0 0 0
Eucalyptus/Pepper Alliance 2.82 2.82 0
Subtotal 2.82 2.82 0
Total Acreage 270.89 117.39 153.5
a
These habitats are protected pursuant to Section 6.1.2 of the WRC MSHCP based on meeting the definition of Riparian/Riverine Areas. b
These habitats are considered high priority for inventory (sensitive) by CNDDB. c Sage Scrub Alliance is comprised of four alliances including Eriogonum fasciculatum Alliance, Salvia leucophylla Alliance, Salvia apiana Alliance, and Salvia mellifera Alliance; only the Salvia apiana Alliance is considered sensitive (high priority for inventory) by CNDDB.

Source: PCR Services Corporation, 2015

4.C. Biological Resources December 2015
City of Corona Skyline Heights Project
PCR Services Corporation/SCH No. 2014021003 4.C-30
Impact 4.C-3 As the project site does not contain any federally protected wetlands, no significant impacts to wetlands would occur. However, the project site supports jurisdictional waters of the U.S. and riparian scrub and streambed. Thus, compliance with applicable regulatory requirements and implementation of the prescribed mitigation measures would reduce potentially significant impacts in these regards to a less than significant level.

The project site does not contain any federally protected wetlands as defined by Section 404 of the CWA. Therefore, no significant impacts to federally protected wetlands would occur as a result of project implementation.

The project site supports 10.2 acres of state jurisdictional streambed, of which 2.16 acres is federal nonwetland jurisdictional area (“waters of the U.S.”). The proposed project will impact 6.17 acre of state jurisdictional streambed, of which 1.57 acres (19,851 linear feet) is federal jurisdictional drainages, as outlined in Table 4.C-3, Impacts to State Streambeds and Federal Drainage Features. Impacts to federal drainage features are depicted on Figure 4.C-5, ACoE Feature Impacts, and impacts to state streambeds are depicted on Figure 4.C-6, CDFW Feature Impacts. The majority of impacts will occur to Feature 3 (F-3; an unnamed blue line stream).

Impacts to jurisdictional features are considered potentially significant. Implementation of Mitigation Measures BIO-6 through BIO-9 would reduce impacts to a less than significant level. Mitigation Measures BIO-6 through BIO-8 outline requirements to obtain regulatory permits prior to the issuance of a grading permit. Specifically, the project Applicant would be required to obtain regulatory permits including a CWA Section 404 permit, a CWA Section 401 Water Quality Certification, and/or a California Fish and Game Code Section 1602 Streambed Alteration Agreement for impacts to jurisdictional features regulated by the USACE, RWQCB, and/or CDFW. Mitigation Measures BIO-1 and BIO-9 outline BMPs to avoid indirect impacts to avoided jurisdictional features.

Table 4.C-3
Impacts to State Streambeds and Federal Drainage Features Feature Impacts to State Streambeds Impacts to Federal Features (including tributaries) Sq. ft. Acres Length Sq. ft. Acres Length F-1 42,594 0.98 6,052 38252 0.88 5232
F-2 191 0.004 191 56 0.001 70
F-3 219,064 5.03 13,776 28,825 0.66 13,232
F-4 0 0 0 0 0 0
F-5 3298 0.08 1986 1427 0.03 1317
F-6 3694 0.08 244 0 0 0
F-7 0 0 0 0 0 0
Totals 268,841 6.17ac 22,249 68,560 1.57 ac 19,851
Source: PCR Services Corporation, 2015

Habitat Impacts FIGURE
Skyline Heights Project 4.C-4
Source: L & L Environmental, Inc., 2015. N

ACoE Feature Impacts FIGURE
Skyline Heights Project 4.C-5
Source: L & L Environmental, Inc., 2015. N

CDFW Feature Impacts FIGURE
Skyline Heights Project 4.C-6
Source: L & L Environmental, Inc., 2015. N

4.C. Biological Resources December 2015
City of Corona Skyline Heights Project
PCR Services Corporation/SCH No. 2014021003 4.C-34
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December 2015 4.C. Biological Resources
City of Corona Skyline Heights Project
PCR Services Corporation/SCH No. 2014021003 4.C-35
(4) Wildlife Movement and Migratory Species
Threshold 4: Interfere substantially with the movement of any native resident or migratory fish or wildlife species or with established native resident or migratory wildlife corridors, or impede the use of native wildlife nursery sites?
Impact 4.C-4 The site contains vegetation suitable for nesting birds. Therefore, the project may result in significant impacts on nesting bird species that are protected under the California Fish and Game Code and the MBTA if removal, clearing, and/or grubbing were to occur during the general avian nesting season (January 1 to September 1). However, implementation of Mitigation Measure BIO-4 would reduce impacts to a less than significant level. Impacts to regional wildlife movement are less than significant and no mitigation is required. (a) Wildlife Movement
The project site does not contain any movement corridors for native resident migratory fish or wildlife species beyond local movement. Wildlife currently move freely throughout the project site and surrounding areas, and upon build-out of the proposed project, are anticipated continue to use open space areas adjacent to the project site to the west and south. Thus, potential impacts to regional movement are considered less than significant and mitigation is not required. It should be noted that Wardlow Wash, which crosses the northernmost tip of the project site, was identified by BonTerra Consulting as a regional wildlife corridor that facilitates movement between the Cleveland National Forest and Prado Basin, as referenced by the Foothill Parkway Westerly Extension DEIR (RBF Consulting 2008). However, Wardlow Wash is relatively constrained by development on either side, road crossings at three locations (Paseo Grande, Serfas Club Drive, and Palisades Drive), and State Route 91 is a significant barrier to wildlife movement. Regardless, Wardlow Wash will be avoided and the proposed project would not inhibit wildlife movement along the drainage; thus, impacts to regional wildlife movement are less than significant and no mitigation is required. (b) Migratory Species The project site contains vegetation suitable for nesting raptors and songbirds, and variety of bird species were observed during biological surveys (as listed in Appendix A of the BRA Report, which is included as Appendix D of this Draft EIR). Therefore, the proposed project may result in significant impacts on nesting bird species that are protected under the California Fish and Game Code and the MBTA if removal, clearing, and/or grubbing were to occur during the general avian nesting season (January 1 to September 1).

Removal, clearing, and/or grubbing of vegetation should be avoided during the general avian nesting season (January 1 to September 1). Any impacts to nesting birds are potentially significant. If removal, clearing, and/or grubbing of vegetation must take place during the nesting season, implementation of Mitigation Measure BIO-2 would reduce these potentially significant impacts to a less than significant level. The mitigation measure would require a nesting bird survey to determine if any nests exist. If nests are found, an exclusion buffer would be established to provide protection to the nesting birds, as determined appropriate by the biologist. A qualified biologist would monitor to determine when nesting activities cease or all young have fledged at which time construction could continue in that area.

4.C. Biological Resources December 2015
City of Corona Skyline Heights Project
PCR Services Corporation/SCH No. 2014021003 4.C-36
(5) Consistency With Regulatory Framework
Threshold 5: Conflict with any local policies or ordinances protecting biological resources, such as a tree preservation policy or ordinance?
Impact 4.C-5 The project is substantially consistent with City policies or ordinances protecting biological resources. Therefore, no significant impact would occur.

The project would not result in the removal of any street trees, which are regulated under the CMC. Chapter

12.22 of the CMC includes the Community Forestry Program, which describes requirements regarding the planning, planting, maintenance, alteration, and removal of all trees, shrubs, and landscape materials on public property. Thus, the proposed project would not conflict with this tree ordinance. Therefore, impacts are not significant and no mitigation is required.

Table 4.C-4 General Plan Consistency Analysis, below, provides an analysis of the project relative to applicable goals and policies regarding biological resources in the Environmental Resources Element of the General Plan. As shown in Table 4.C-3, the project is consistent with the goals and policies including a Table 4.C-4
General Plan Consistency Analysis
Goals and Policies Consistency
Environmental Resources - Biological Resources
Goal 10.6 - Protect, enhance, and sustain significant
plant and wildlife species and habitat, which exist in
Corona and its Planning Area for the long term benefit
of the natural environment, and Corona residents and
visitors.

Consistent. Technical biological reports were prepared
for the project by Gonzales Environmental Consulting, LLC (GEC 2014a through 2014g), and updated by L&L
Environmental, Inc. (L&L 2015a through 2015c), An
analysis of special-status plant and wildlife species and sensitive habitats is provided in the BRA report (L&L
2015a) and in this EIR, and appropriate mitigation is
proposed to offset any potentially significant impacts.

Policy 10.6.2: Preserve the species and habitats listed in Tables 4.2-1 and 4.2-2 of the Technical Background
Report and those that may be considered by the City of
Corona in the future.

Consistent. A review of CNDDB and CNPS databases was
conducted for species with potential to occur within the vicinity and an analysis of special-status plant and wildlife species and sensitive habitats is provided in the BRA
Report (L&L 2015a) and in this EIR. Appropriate
mitigation is proposed to offset any potentially significant impacts, including impacts to riparian habitats. The
mitigation will result in a no-net-loss of habitat and, in some cases, a net gain of habitat which will be preserved.

Policy 10.6.3: Acquire and maintain the most current
technical information available regarding the status,
location, and condition of significant and sensitive
biological species and habitats as well as assessments
of potential for impacts on those resources and how
such resources should be appropriately protected,
conditions sustained, and impacts mitigated from
nearby development. Consistent. Technical biological reports were prepared for the project by Gonzales Environmental Consulting, LLC (2014a through 2014g), and updated by L&L
Environmental, Inc. (L&L 2015a through 2015c). A review of CNDDB and CNPS databases was conducted for species
with potential to occur within the vicinity and an analysis of special-status plant and wildlife species and sensitive habitats is provided in the BRA Report (L&L 2015a) and in this EIR. Appropriate mitigation is proposed to offset any potentially significant impacts.

December 2015 4.C. Biological Resources
Table 4.C-4 (Continued)
General Plan Consistency Analysis
City of Corona Skyline Heights Project
PCR Services Corporation/SCH No. 2014021003 4.C-37
Goals and Policies Consistency
Policy 10.6.4: Participate and enroll in the Western
Riverside County Multiple Species Habitat
Conservation Plan (MSHCP) to conserve biological
diversity through protection of natural communities.

Consistent. The project site is located within the WRC
MSHCP. The project site is located within the Burrowing Owl Survey Area and focused surveys were conducted for
this species; however, no burrowing owls were found on- site. The project site is located outside the Stephens’ kangaroo rat mitigation fee area. The Applicant would pay the required MSHCP development mitigation fee.

Impacts to riparian/riverine resources will be mitigated as proposed in the DBESP Report (L&L 2015c).

In addition, project design features have been
incorporated to address potential indirect effects as result of the urban/wildlands interface and it is anticipated they will be incorporated within the project conditions of
approval.

Goal 10.7 – Ensure that biological resources are not
impacted during or as a result of construction and
development activity.

Consistent. A full analysis of impacts on biological
resources is provided in the MSHCP Consistency Analysis Report (GEC 2014f), the update prepared by L&L
Environmental, Inc. (L&L 2015a) and in this EIR.

Recommended mitigation measures would require
mitigation for sensitive plant species and communities, biological monitoring during construction, and pre- construction nesting bird surveys, which would reduce the potential impacts to a less than significant level.

Policy 10.7.1: Require that construction activities be
conducted in a manner to minimize adverse impacts on
natural resources through the use of Best Management
Practices, as established and updated by the City of
Corona.

Consistent. BMPs will be implemented as part of the
storm water pollution prevention measures for the
project, in accordance with all appropriate National
Pollutant Discharge Elimination System (NPDES)
requirements.

Policy 10.7.2 – Where applications for development are
being proposed in undeveloped areas of the City and the SOI areas, or in areas that an Initial Study has determined there is potential for significant adverse impacts to
biological resources, an Environmental Impact Report
(EIR) or a Mitigated Negative Declaration (MND) shall be undertaken by the proponent. As part of these studies,
the proponent shall also submit a biological resources
technical report with the following qualifications:
a) The report must be prepared by a qualified
professional who addresses the proposed project’s
impact on federally and State-listed and candidate
plants and animals; California Department of Fish
and Game (CDFG)3 Special Animals; natural
communities of high inventory priority with the
California Natural Diversity Database (CNDDB);
and any other special interest species or
Consistent. Technical biological reports were prepared
for the project by Gonzales Environmental Consulting, LLC (GEC 2014a through 2014g) and updated by L&L
Environmental, Inc. (L&L 2015a through 2015c). An
analysis of special-status plant and wildlife species and sensitive habitats is provided in the BRA Report (L&L
2015a) and in this EIR, and appropriate mitigation is
proposed to offset any potentially significant impacts. 3 It should be noted that California Department of Fish and Game changed its name to California Department of Fish and Wildlife as of January 1, 2013.

4.C. Biological Resources December 2015
Table 4.C-4 (Continued)
General Plan Consistency Analysis
City of Corona Skyline Heights Project
PCR Services Corporation/SCH No. 2014021003 4.C-38
Goals and Policies Consistency
communities identified in the General Plan
Technical Background Report, or those hereafter
named by federal or State trustee agencies.
b) If appropriate habitat for any listed species occurs on the site, a qualified biologist shall conduct
focused surveys according to USFWS and/or CDFG
protocol.
c) A qualified botanist shall conduct a focused rare
plant survey during the appropriate time of year
following USFWS and/or CDFG protocol.
d) If any listed species would potentially be impacted
by the proposed project, consultation with USFWS
and/or CDFG would be required to identify
mitigation measures to avoid, minimize, or
compensate for impacts. These mitigation
measures would be included in the report.
e) The report shall also define a program for
monitoring and evaluating the effectiveness of the
specified mitigation measures.

Goal 10.9 – Protect natural and biological resources
within riparian corridors and wetlands.

Consistent. The project site does not contain any
wetlands. Appropriate mitigation is proposed to offset
any potentially significant impacts to resources within riparian corridors (Mitigation Measures BIO-6 through
BIO-9 and BIO-12).

Policy 10.9.1: Review proposed developments in
riparian and wetland habitats to evaluate their
conformance with the following policies and standards:

Full consideration of the nature of existing
biological resources present and all reasonable
measures that shall be taken to avoid
significant impacts, including retention of
sufficient natural open space and undeveloped
buffer zones.

Development shall be designed and sited to
preserve watercourses, riparian habitat, vernal
pools, and wetlands in their natural condition,
unless these actions result in an infeasible
project.

Where riparian corridors are retained, they
shall be protected by an adequate buffer with a
minimum 100 foot protection zone from the
edge of the tree, shrub, or herb canopy.

Development shall incorporate habitat
linkages (wildlife corridors) to adjacent open
spaces, where appropriate.

Development shall incorporate fences, walls,
vegetative cover, or other measures to
adequately buffer habitat areas, linkages, or
corridors from the built environment.

Consistent. The proposed project avoids impacts to
jurisdictional drainage features to the maximum extent
practicable and was designed to avoid 117.39 acres of
natural habitat. However, the proposed project will
impact 6.17 acres of state jurisdictional streambed and riparian habitat, of which 1.57 acres (19,851 linear feet) is federal jurisdictional drainage features. Appropriate
mitigation is proposed to offset any potentially significant impacts to riparian resources (Mitigation Measures BIO-6 through BIO-9 and BIO-12). In addition, project design
features have been incorporated to address potential
indirect effects as result of the urban/wildlands interface, and it is anticipated they will be incorporated within the project conditions of approval. The project is providing protection zone buffers between the development and the vegetation canopy in the avoided drainage features.

December 2015 4.C. Biological Resources
Table 4.C-4 (Continued)
General Plan Consistency Analysis
City of Corona Skyline Heights Project
PCR Services Corporation/SCH No. 2014021003 4.C-39
Goals and Policies Consistency
Roads and utilities shall be located and
designed such that conflicts with biological
resources, habitat areas, linkages, or corridors
are avoided.

Development shall utilize appropriate open
space or conservation easements in order to
protect sensitive species or their habitats.

Development shall mitigate unavoidable
adverse impacts to waters of the United States,
wetlands, and riparian habitat by replacement
on an in-kind basis (i.e., riparian habitat is to
be replaced by riparian habitat of the same
type). Replacement shall be based on a ratio
determined by the California State Fish and
Game Department and/or the Army Corps of
Engineers in order to account for the
potentially diminished habitat value of
replacement habitat. Such replacement shall
occur on the original development site,
whenever possible. Alternatively, replacement
can be effected, subject to State and Federal
regulatory approval, by creation or restoration
of replacement habitats elsewhere, preferably
within Corona’s Planning Area. Replacement
habitats are to be protected in perpetuity
through acquisition, an appropriate
conservation easement, or dedication.

Policy 10.9.2: Prohibit development and grading that
alters the biological integrity of riparian corridors,
unless no feasible alternative exists or the damaged
habitat is replaced with habitat of equivalent value.

Development that is permitted with riparian corridors
shall be based on field evidence and interpretation of
physical and biological data that shall include the
following:

The nature and extent of the vegetation, or in
the case of disturbed sites, the potential
vegetation
Topography
Hydrology
Consistent. The proposed project avoids impacts to
jurisdictional drainage features to the maximum extent
practicable. However, the proposed project will impact

6.17 acres of state jurisdictional streambed and riparian habitat, of which 1.57 acres (19,851 linear feet) is federal jurisdictional drainage features. Appropriate mitigation is proposed to offset any potentially significant impacts to riparian resources (Mitigation Measures BIO-6 through
BIO-9 and BIO-12). Policy 10.10.4 – Maintain and conserve superior examples of native trees, natural vegetation, stands of established trees, and other features for ecosystem,
aesthetic, and water conservation purposes.

Consistent. The proposed project avoids impacts to
jurisdictional drainage features to the maximum extent
practicable, and was designed to avoid 117.39 acres of
natural habitat. Furthermore, appropriate mitigation is proposed to offset any potentially significant impacts to sensitive biological resources.

Policy 10.10.5 – Conserve the oak tree resources in the Consistent. The project site supports 1.17 acres of Coast

4.C. Biological Resources December 2015
Table 4.C-4 (Continued)
General Plan Consistency Analysis
City of Corona Skyline Heights Project
PCR Services Corporation/SCH No. 2014021003 4.C-40
Goals and Policies Consistency
City and SOI areas. Live Oak Alliance. These proposed project is within the County of Riverside but is proposed for annexation into the City of Corona; thus, impacts to oaks are analyzed
under the City’s regulations (although the County of
Riverside also regulates oak trees within the Oak Tree
Management Guidelines). The proposed project will
impact only 0 .1 acre of the total 1.17 acres on the project site. Mitigation for oak trees is proposed to replace trees at a minimum 1:1 ratio within landscaped areas
(Mitigation Measure BIO-10). Oak tree mitigation may
also be incorporated into mitigation proposed for riparian habitat, as outlined in Mitigation Measure BIO-12.

Source: City of Corona General Plan, ICF International, and PCR Services Corporation. mitigation measure to compensate for impacts to oak trees (Mitigation Measure BIO-10). As such, impacts would be less than significant.

In summary and based on the above discussion, the proposed project would not conflict with any local policies or ordinance protecting biological resources, including a tree preservation policy or ordinance. (6) Habitat Conservation Plans and Natural Community Conservation Plans Threshold 6: Conflict with the provisions of an adopted Habitat Conservation Plan, Natural Community Conservation Plan, or other approved local, regional, or state habitat conservation plan? Impact 4.C-6 The project site supports riparian/riverine habitat that will be mitigated as proposed in the DBESP Report; therefore, impacts would be less than significant. Additionally, the Applicant would pay the required MSHCP development mitigation fee.

The project site is located within the Temescal Canyon Area Plan of the WRC MSHCP and would comply with the WRC MSHCP. The project site is not within a Criteria Cell, nor is it within the Narrow Endemic Plant Species, Criteria Area Species, Amphibian Species, or Mammal Species Survey Areas. The project is also not located within a MSHCP designated Core or Linkage and will not impact overall Reserve Assembly goals, although the project does adjoin PQP (public quasi-public) and would isolate a 10-acre PQP parcel. None of the identified Planning Species for the Temescal Canyon Area Plan have been located within the survey area.

The project site is located within the Burrowing Owl Survey Area and focused surveys were conducted for this species; however, no burrowing owls were found on-site. The project site is located outside the Stephens’ kangaroo rat mitigation fee area and the SKR HCP. The Applicant would pay the required MSHCP development mitigation fee. Project compliance with the WRC MSHCP is outlined below.

December 2015 4.C. Biological Resources
City of Corona Skyline Heights Project
PCR Services Corporation/SCH No. 2014021003 4.C-41
(a) Cores and Linkages
The project is not within any MSHCP designated Core or Linkage areas but is located adjacent to a large expanse of open space within Core B to the east and the Cleveland National Forest. As such, the project has the potential to minimally affect Core B, although in most areas the Core is separated from the proposed impact area by undeveloped land and topographic changes. Furthermore, wildlife currently moves freely throughout the project site and surrounding areas via existing travel routes such as drainages, ridgelines, and existing dirt roads. It should be noted that the main drainages for Feature 6 (Mabey Canyon Wash) and Feature 7 (Wardlow Wash) are mostly (Feature 6) or entirely (Feature 7) being avoided. Wardlow Wash was identified by BonTerra Consulting as a regional wildlife corridor that facilitates movement between the Cleveland National Forest and Prado Basin, as referenced by the Foothill Parkway Westerly Extension DEIR (RBF Consulting 2008).
(b) Public Quasi-Public (PQP) Lands
The proposed Project is outside of public quasi-public (PQP) lands. The survey area adjoins PQP properties to the north, west and south. With the implementation of the project a single 10 acre PQP parcel is surrounded by the survey area and is bordered to the west, north and east by the proposed development and the Foothill Parkway. Although not all of the land surrounding the 10 acre parcel is proposed for development, this parcel and adjacent habitat avoided by the proposed Project will be isolated from the larger MSHCP Core B area to the west by the proposed Project.

The MSHCP (Section 3.2.1) requires that if an MSHCP permittee alters PQP land in such a way that it no longer contributes to the reserve assembly, the permittee will replace the land at a ratio no less than 1:1 and the replacement must be biologically equivalent or superior. Ten acres of habitat adjacent to Forest Service land will be avoided as compensation for the isolation of the 10 acre PQP parcel, as shown in Figure 4.C-7, Compensation Parcel, and will be deed restricted to prevent future impacts.

The existing PQP parcel is 10 acres in the foothills east of the proposed project and would remain. The parcel supports two jurisdictional features and approximately 10 acres of dry scrub habitat; 9 acres of chaparral Alliance and 1 acre of sage scrub Alliance. The parcel is crossed on the east side by a dirt access road and is a part of the general area being used for recreational purposes. The site is on the edge of development, approximately 525 feet from agricultural development to the southeast, 650 feet from medium density residential development to the east and is immediately adjacent to the proposed Foothill Parkway impact area. The parcel is a part of the general area being used for recreational purposes.

The 10 acre parcel proposed for compensation is in the far west portion of the survey area, very close to the isolated parcel; in the same area of the Santa Ana foothills. The compensation parcel supports 10 acres of chaparral Alliance and two jurisdictional features. There are no access roads on the property. The proposed development is adjacent to the compensation parcel, but only a narrow east/west band of the development comes close to the parcel. Another seven acres of natural land contiguous (or adjacent) to the ten acre compensation parcel will be avoided by the development, and will remain undeveloped. The proposed parcel is immediately adjacent to PQP land, MSHCP Core B, and would add to the total acreage of contiguous land within the Core. Proposed mitigation measures will increase the size of natural land associated with Core B of the MSHCP Conservation Areas and will provide a larger area to be utilized by a wide variety of species for dispersal, seasonal migration and home range connectivity. These includes Mitigation Measure BIO-11, preserving a 10 acre block of natural land adjacent to the Forest Service land and Core B, and

4.C. Biological Resources December 2015
City of Corona Skyline Heights Project
PCR Services Corporation/SCH No. 2014021003 4.C-42
Mitigation Measure BIO-12, preserving avoided resources within the survey area to the extent feasible in open space areas placed within a deed restriction or other appropriate legal mechanism to prevent future development,. There would be no loss to the overall acreage or quality of PQP lands; the existing PQP lands would remain in addition to the compensation parcel. (c) Burrowing Owl Survey Area Focused surveys were conducted for burrowing owl in May, June and July 2013 and this species was not observed on-site. However, based on the presence of suitable habitat and in compliance with the WRC MSHCP, a 30-day pre-construction survey for burrowing owl will be conducted prior to earth disturbance (i.e., construction), as outlined in Mitigation Measure BIO-3. Measures are also proposed should burrowing owl be observed during the pre-construction survey. With the implementation this mitigation measure, impacts to burrowing owls would be reduced to a less than significant level. (d) Riparian/Riverine
All of the habitat and drainages beds identified as state jurisdictional areas were also identified as Riparian/Riverine as defined by Section 6.1.2 of the WRC MSHCP. As such, the project site supports 10.2 acres of state jurisdictional and Riparian/Riverine Areas, of which 6.17 acres are proposed for impacts including Sycamore Alliance (0.32 acre), Mulefat Alliance (0.09 acre), Willow Alliance (0.21 acre), Oak Alliance (0.1 acre) and streambeds with upland habitat (5.45 acres). An impacts map is provided as Figure

4.C-8, MSHCP Riparian/Riverine Impacts. Impacts are also summarized in Table 4.C-5, Impacts and Avoidance of Riparian/Riverine Areas and Table 4.C-6, Impacts and Avoidance of Riparian Habitat. Impacts to riparian/riverine resources are potentially significant. However, as required under Section 6.1.2 of the WRC MSHCP, impacts will be mitigated at a biologically equivalent or superior level as proposed in the DBESP Report to ensure that functions and values of the riparian/riverine resources are not lost, as detailed in Mitigation Measure BIO-12. The DBESP Report is provided in Appendix D of this Draft EIR (L&L 2015c).

Therefore, the proposed project would not conflict with the provisions of the WRC MSHCP, and impacts would be reduced to less than significant. Table 4.C-5
Impacts and Avoidance of Riparian/Riverine Areas
MSHCP

6.1.2 Features On-site
Avoided
(acres)
Project
Impacts
(acres)
Percent
Avoided
Percent
Impacted
Upland or Unvegetated
Riverine Features 7.31 1.86 5.45 25% 75%
Riparian Vegetated
Features 2.89 2.17 0.72 75% 25%
TOTAL 10.2 4.03 6.17 100% 100%
Source: PCR Services Corporation, 2015

Compensa on Parcel FIGURE
Skyline Heights Project 4.C-7
Source: L & L Environmental, Inc., 2015. N

MSHCP Riparian/Riverine Impacts FIGURE
Skyline Heights Project 4.C-8
Source: L & L Environmental, Inc., 2015. N

December 2015 4.C. Biological Resources
City of Corona Skyline Heights Project
PCR Services Corporation/SCH No. 2014021003 4.C-45
(e) Urban/Wildlands Interface
The guidelines presented in WRC MSHCP Section 6.1.4, Guidelines Pertaining to the Urban/Wildlands Interface are intended to address indirect effects associated with locating development in proximity to the MSHCP Conservation Area. Development located in proximity to the MSHCP Conservation Area may result in edge effects that will adversely affect biological resources within the Conservation Area. Indirect impacts are considered to be those impacts associated with the project that involve the effects of alteration of the existing habitat and an increase in human population within the study area. These impacts are commonly referred to as “edge effects” and may result in changes in the behavioral patterns of wildlife and reduced wildlife diversity and abundance in habitats adjacent to the study area. Indirect impacts include the effects of increases in ambient levels of sensory stimuli (e.g., noise and light), unnatural predators (e.g., domestic cats and other non-native animals), competitors (e.g., exotic plants and non-native animals), and trampling and unauthorized recreational use due to the increase in human population. Other permanent indirect effects may occur that are related to water quality and storm water management, including trash/debris, toxic materials, and dust.

Indirect effects resulting from the proposed project may occur within the MSHCP Conservation Area if the PDF BIO-1 through PDF BIO-9, discussed above under Project Design Features, are not implemented.

Therefore, to minimize indirect effects at the urban/wildlands interface, the following measures shall be incorporated into the PDFs to ensure consistency with WRC MSHCP Section 6.1.4, Guidelines Pertaining to the Urban/Wildlands Interface. 3. CUMULATIVE IMPACTS
The geographic area for cumulative analysis regarding biological resources is the WRC MSHCP area, within which is the City of Corona General Plan. The project would not result in significant impacts to biological resources, including endangered or threatened species, plant communities, habitat fragmentation and wildlife movement, local policies and ordinances, or habitat conservation plans, based on the lack of impacts to these resources or the proposed mitigation measures to mitigate impacts. Cumulative development in the greater region has been considered and impacts minimized and mitigated for under the WRC MSHCP. By meeting the MSHCP requirements the project’s contribution to the regional impact would not be Table 4.C-6
Impacts and Avoidance of Riparian Habitat
Riparian Habitat On-site
Avoided
(acres)
Project
Impacts
(acres)
Percent
Avoided
Percent
Impacted
Mulefat Alliance 1.14 1.05 0.09 92 8
Coast Live Oak Alliance 1.17 1.07 0.10 91 9
Sycamore Alliance 0.37 0.05 0.32 13.5 86.5
Willow Alliance 0.21 0 0.21 0 100
TOTAL 2.89 2.17 0.72 Source: PCR Services Corporation, 2015

4.C. Biological Resources December 2015
City of Corona Skyline Heights Project
PCR Services Corporation/SCH No. 2014021003 4.C-46
cumulatively considerable. Future projects in the vicinity would also be subject to MSHCP requirements and mitigation, although additional development in the project vicinity is expected to be limited due to its proximity to widespread natural open space on National Forest lands and the WRC MSHCP Core B.

Therefore, since the project is in compliance with the WRC MSHCP, will participate in the WRC MSHCP including payment of mitigation fees, and proposes addition mitigation measures, the project would not contribute to significant cumulative impacts to biological resources.

4. MITIGATION MEASURES
Based on the analysis above, the proposed project could result in a potentially significant impact with regard to special-status plant and wildlife species, sensitive plant communities, jurisdictional features, nesting birds, and MSHCP riparian/riverine resources. Therefore, the following mitigation measures are recommended:

Vegetation and Sensitive Species
Vegetation and General Wildlife
Mitigation Measure BIO-1: The Project impact areas and avoidance areas shall be flagged or fenced prior to grubbing of any vegetation or jurisdictional drainage features to prevent incursion into unsurveyed or avoided areas. Qualified biological monitor(s) shall conduct periodic monitoring during construction as deemed appropriate, to ensure the flagging or fencing remains intact and no incursions into avoided areas occurs, and to flush any wildlife within the project impact footprint away from work areas. The following BMPs shall be adopted prior to and during construction to ensure biological resources within open space areas surrounding the proposed project will not be adversely affected:

The project impact footprint shall be surveyed, staked, and flagged and/or fenced (e.g., with flagging tape, snow fencing or silt fencing) by a surveyor and the boundary shall be confirmed by a qualified biological monitor. The construction site manager shall ensure that the fencing is maintained for the duration of construction and that any required repairs are completed in a timely manner.

Maintenance activities shall not commence until 0700 hours and shall be completed before dusk each day to the extent feasible. If any wildlife is encountered during maintenance activities, the wildlife shall be allowed to leave the work area unharmed and shall be flushed or herded in a safe direction away from the work area(s).

Any open trenches shall be covered at the end of each work day in a manner to prevent the entrapment of wildlife, or adequately ramped to provide an animal escape.

If night-time maintenance is required, lighting shall be directed away from native vegetation and should be limited to the minimum amount necessary to complete the maintenance activities.

Staging or storage areas shall occur outside of any drainages. Storage of potentially hazardous materials, including but not limited to fuel, paint, stains, pesticides, herbicides, solvents, and oils shall not be permitted within 50 feet of any habitat area

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to be retained by the project. During construction, disposal of such material shall occur in a controlled area that is physically separated from potential storm water runoff.

Any equipment or vehicles driven and/or operated within or adjacent to ponded or flowing water within any drainages shall be checked and maintained daily, to prevent leaks of materials that, if introduced to water, could be harmful to aquatic species.

All vehicles and equipment shall be maintained in proper working condition to minimize fugitive emissions and accidental spills from motor oil, hydraulic fluid, grease, or other fluids or hazardous materials. Maintenance and refueling of construction equipment shall be limited to areas specified as appropriate by the project biologist. All fuel or hazardous waste leaks, spills, or releases shall be stopped or repaired immediately and cleaned up at the time of occurrence. All spill material removed shall be disposed of at an appropriate off-site landfill. Maintenance vehicles shall carry appropriate equipment and materials to isolate and remediate leaks or spills, such as a spill containment kit.

Stationary equipment such as motors, pumps, or generators, located within or adjacent to ponded or flowing water within drainages shall be positioned over drip pans.

No equipment maintenance shall be done within or adjacent to ponded or flowing water within drainages where petroleum products or other pollutants from the equipment may enter into the water.

No waste, cement, concrete, asphalt, paint, oil, or any other substances used during maintenance activities which could be hazardous to aquatic life, or other organic or earthen material, shall be allowed to contaminate the soil and/or enter into or be placed where it may be washed by rainfall or runoff into ponded or flowing water within any drainages. Any of these materials placed where they may affect ponded or flowing water shall be removed immediately upon observation. When operations are completed, any excess non-native materials shall be removed from the work area.

All litter and pollutions laws shall be followed. All refuse created or brought on site by personnel or contractors shall be placed in covered containers, removed from the site daily, and disposed of properly. All exposed/disturbed areas shall be stabilized to the greatest extent possible using appropriate, industry standard erosion control measures.

No maintenance activities shall occur during active precipitation. If any precipitation is forecasted, the work area shall be secured at least one day prior so no materials enter or wash into any drainages.

Field crews shall maintain the speed limit on posted roads and limit vehicle/truck speeds on unpaved surfaces to 15 miles per hour
Sensitive Wildlife
Mitigation Measure BIO-2: To prevent impacts to sensitive, migratory and nesting birds, including raptors, clearing or other work in native habitats shall be avoided during the critical nesting period of January 1 – September 1. If work cannot be avoided during this timeframe, a nesting bird survey will be conducted within three days prior to clearing and/or grading, by a qualified biologist. If present, a nesting bird plan will be developed and implemented to include appropriate measures to mitigate the potential impacts, such

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as maintaining a buffer area until fledging has occurred as determined appropriate by the biologist. Active bird nests should be mapped utilizing a hand-held global positioning system (GPS) (getting as close as possible without disturbing the nest) and a buffer will be flagged around the nest (typically 300’ for most species, 500’ buffer for raptor nests, as determined appropriate by the biologist). Construction should not be permitted within the buffer areas while the nest continues to be active (eggs, chicks, etc.). Once fledging has occurred no further avoidance is required.

Mitigation Measure BIO-3: A pre-construction burrowing owl clearance survey shall be conducted no more than 30 days before earth disturbance (construction) by an experienced burrowing owl biologist. The surveys will be conducted as close to the actual construction initiation date as possible.

If burrowing owls are determined present following the pre-construction survey, occupied burrows shall be avoided to the greatest extent feasible, following the guidelines in the CDFW’s Staff Report on Burrowing Owl Mitigation (March 7, 2012) including, but not limited to, avoiding occupied burrows during the nesting and non-breeding seasons, implementing a worker awareness program, biological monitoring, establishing avoidance buffers, and flagging burrows for avoidance with visible markers. If occupied burrows cannot be avoided, acceptable methods may be used to exclude burrowing owl either temporarily or permanently, pursuant to a Burrowing Owl Exclusion Plan that shall be prepared and approved by CDFW. The Burrowing Owl Exclusion Plan shall be prepared in accordance with the guidelines in the Staff Report on Burrowing Owl Mitigation.

Invasive Vegetation Control (see also proposed PDFs outlined in Impact 4.C-6, section (5)) Mitigation Measure BIO-4: All heavy equipment shall be washed, particularly the wheels and under carriage, prior to entering the project site from other construction sites to prevent the spread of weedy species.

Mitigation Measure BIO-5: Staging areas shall be placed in areas that have been previously disturbed or have degraded habitat within the project footprint, but do not show an infestation of non-native species. Staging areas will be maintained in a weed/noxious weed-free condition.

Jurisdictional Drainage Features
Mitigation Measure BIO-6: To mitigate for the loss of 1.57 acres of non-wetland federal jurisdictional drainage features (“waters of the U.S. [WoUS]) due to project construction, the project Applicant shall enter into an agreement with the U.S. Army Corps of Engineers (via issuance and implementation of a Nationwide permit or Individual permit) to replace affected WoUS at a ratio specified by the U.S. Army Corps of Engineers at no less than a 1:1 basis, through off-site acquisition and preservation, participation in an approved mitigation bank, and/or on- or off-site creation, enhancement or reestablishment of WoUS or a combination of these options. The exact ratio shall be based on U.S. Army Corps of Engineers mitigation guidelines pursuant to their approval. Preparation of a Habitat Mitigation and Monitoring Plan (HMMP) outlining the details of the mitigation

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shall be required for on-site mitigation or off-site mitigation on lands other than those pre-approved by the U.S. Army Corps of Engineers. Mitigation Measure BIO-7: To mitigate for the loss of 1.57 acres of non-wetland federal jurisdictional drainage features (“waters of the U.S. [WoUS]) due to project construction, the project Applicant shall enter into an agreement with the California Regional Water Quality Control Board (via issuance and implementation of a Clean Water Act Section 401 Certification) to replace affected WoUS at no less than a 1:1 basis, as specified by the California Regional Water Quality Control Board, through a combination of off-site acquisition and preservation, participation in an approved mitigation bank, and/or on- or off-site creation, enhancement or reestablishment of WoUS. The exact ratio shall be based on a functions and values assessment pursuant to their approval. Preparation of a Habitat Mitigation and Monitoring Plan (HMMP) outlining the details of the mitigation shall be required for on-site mitigation or off-site mitigation on lands other than those pre-approved by the U.S. Army Corps of Engineers. Mitigation Measure BIO-8: To mitigate for the loss of 6.17 acres of streambed and riparian vegetation due to project construction, the project Applicant shall enter into an agreement with the California Department of Fish and Wildlife (via issuance and implementation of a Streambed Alteration Agreement, Section 1600) to replace affected streambed at no less than a 1:1 basis, as specified by the California Department of Fish and Wildlife, through a combination of off-site acquisition and preservation, participation in an approved mitigation bank, and/or on- or off-site creation, enhancement or reestablishment of the streambed. The exact ratio shall be based on a functions and values assessment pursuant to their approval. Preparation of a Habitat Mitigation and Monitoring Plan (HMMP) outlining the details of the mitigation shall be required for on- site mitigation or off-site mitigation on lands other than those pre-approved by the U.S.

Army Corps of Engineers.

Mitigation Measure BIO-9: The project proponent shall employ all standard best management practices (BMPs) to prevent discharges from entering avoided waters of the U.S. and streambed with associated riparian vegetation during construction. BMPs, such as the following, shall be enforced (see also BIO-1):
the use of erosion control or sedimentation prevention methods, such as fiber rolls, sand bags, rice mats, straw wattles or similar measures, where appropriate; the proper use and disposal of oil, gasoline, diesel fuel, antifreeze and other toxic substances.

City of Corona General Plan Oak Tree Avoidance
Mitigation Measure BIO-10: Oak trees impacted by the project shall be replaced at no less than a 1:1 ratio in the landscape areas, as approved by the City of Corona. Western Riverside County Multiple Species Habitat Conservation Plan Mitigation Measure BIO-11: The ten (10) acres of natural habitat identified as a compensation parcel adjacent to Forest Service land shall be preserved in perpetuity pursuant to a deed restriction or other appropriate legal mechanism to prevent future development.

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Mitigation Measure BIO-12: Mitigation shall be provided for the 6.17 acre of Riparian/Riverine impacts at no less than a 1:1 basis, as determined through consultation with the City of Corona and wildlife agencies based on their approval of the Determination of Biologically Equivalent or Superior Preservation report that provides a functions and values analysis pursuant to the requirements of the Western Riverside County Multiple Species Habitat Conservation Plan. The project Applicant proposes mitigation at a ratio of 2:1 for riparian habitat and 1:1 for riverine habitat in the form of off-site mitigation with the Riverside- Corona Resource Conservation District (RCRCD). In the event mitigation with the RCRCD is not finalized for any reason, equal or greater value mitigation shall be provided in the form of one or more of the following: off-site acquisition and preservation, participation in an approved mitigation bank, on-site or off-site creation, enhancement or reestablishment. If off-site mitigation is incorporated, the preferred choice shall be to find mitigation within or adjacent to the Santa Ana Watershed and in or adjacent to Corona if possible. In addition, avoided resources within the open space areas shall be preserved to the extent feasible pursuant to a deed restriction or other appropriate legal mechanism to prevent future development.

If on-site mitigation is proposed as an alternative mitigation, a Habitat Mitigation and Monitoring Plan (HHMP) will be developed and provided for review and approval by the local and regulatory agencies and shall include, at minimum, the following:

Quantitative success criteria (vegetation cover and species richness); Recommendations for soil preparation;
A plant palette to include native species occurring on the project site, such as coast live oak and Coulter’s matilija poppy if feasible;
Planting methods;
Irrigation and maintenance requirements; and
A long-term mitigation maintenance and monitoring plan with remedial measures. 5. LEVEL OF SIGNIFICANCE AFTER MITIGATION With implementation of the above Project Design Features and mitigation measures, impacts associated with biological resources would be reduced to a less than significant level.

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4. ENVIRONMENTAL IMPACT ANALYSIS
D. CULTURAL RESOURCES

INTRODUCTION
The purpose of this section is to evaluate potential impacts on cultural resources including historical, archaeological, and paleontological resources that could occur with implementation of the project. The additional 150.3-acre area beyond the 270.9-acre area to be developed as part of the project, but within the overall 394.8-acre annexation area, would not be physically impacted as a result of project implementation.

As such, this analysis focuses on the 270.9-acre development footprint area within the project site that would be physically impacted by the project.

The analysis of cultural resources presented in this section is derived from technical reports prepared by LSA Associates, Inc. including: Supplementary Cultural Resources Assessment for the Skyline Heights Project (TTM 36544) in the City of Corona, Riverside County, California (dated April 22, 2014); Supplementary Paleontological Research for Expanded Study Area of the Skyline Heights Project (TTM 36544) in the City of Corona, Riverside County (dated April 22, 2014); and Update to Paleontological Resources Report for the Skyline Heights Project (TTM 36544) in the City of Corona, Riverside County, California (dated May 9, 2013). These technical reports are provided for reference in Appendix E of this Draft EIR.

1. ENVIRONMENTAL SETTING
a. Existing Conditions
(1) Cultural Setting
(a) Native American Ethnographic Setting1 The project area lies on the edge of the traditional cultural territory of the Gabrielino/Tongva and Luiseño groups, but may also have been occupied by the Cahuilla as a result of population shifts over time. These tribes all belong to a cultural group that speaks a language of the Takic branch of the Shoshonean family, part of the larger Uto-Aztecan language stock.

Among the inland Cahuilla and the Luiseño, subsistence was based on hunting, collecting, and harvesting.

Clans were apt to own land in valley, foothill, and mountain areas, providing them with the resources of many different ecological niches. Individual lineages or families owned specific resource areas within the clan territory. Most inland Luiseño clans also owned fishing and gathering sites on the coast, also part of Luiseño territory. Although any given village had access to a wide array of necessary resources, flourishing systems of trade and exchange gave them access to the resources of their neighboring villages and of distant peoples.
1 Final Corona Regional Medical Center Expansion Project Archaeological and Paleontological Resources Report, prepared by ICF International, April 2013.

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Gabrielino/Tongva subsistence was based on a composite hunting and gathering strategy that included large and small land animals, sea mammals, river and ocean fish, and a variety of vegetal resources. Acorns were a major food staple, but the roots, leaves, seeds, and fruit of many other plants also were used. Generally, Gabrielino settlements were created at the intersection of several ecozones. The majority of the population drifted as families to temporary hillside or coastal camps throughout the year, returning to the central location on ritual occasions or when resources were low and it was necessary to live on stored foods.

Gabrielino/Tongva territory included the watersheds of the San Gabriel, Santa Ana, and Los Angeles Rivers; portions of the Santa Monica and Santa Ana Mountains; the Los Angeles Basin; the coast from Aliso Creek to Topanga Creek; and San Clemente, San Nicolas, and Santa Catalina Islands. The Gabrielino/Tongva had a rich and varied material culture. Technological and artistic items included shells set in asphaltum, carvings, paintings, an extensive steatite industry, baskets, and a wide range of stone, shell, and bone objects that were both utilitarian and decorative.

The Gabrielino/Tongva inhabited some 50 to 100 permanent villages in fertile lowlands along streams and rivers and in sheltered areas along the coast at the time of European contact. Larger permanent villages most likely had populations that averaged 50 to 200 persons. Sedentary villages also had smaller satellite villages at varying distances; these remained connected to the larger villages through economic, religious, and social ties. The Native American village nearest the project site was at Temescal Hot Springs, while the largest Native American village near the project was that of Hurumpa, located on the southern edge of what is now the City of Riverside.
(b) Prehistoric Cultural Setting2 Occupation of the region appears to have begun approximately 9,000 years before present (BP), based on excavations at sites near Lake Elsinore and in Diamond Valley Lake. Reports produced as a result of recent large-scale excavations at Diamond Valley Lake provide extensive detail of the prehistory of the inland region.

The chronology developed for the Diamond Valley Lake Project, based on radiocarbon dates and projectile point typology, is similar to that of Warren in the early phases of prehistory. The Diamond Valley Lake chronology begins with the Paleo Indian period dating from 12,000 to 9,500 BP. The Early Archaic (9,500– 7,000 BP), Middle Archaic (7,000–4,000 BP), and Late Archaic 4,000–1,500 BP) Periods correlate with Warren’s chronology, which is the latter part of the Lake Mojave, the Pinto, and the Gypsum Periods. In most aspects, the Diamond Valley Lake sites appear to exhibit the same composition and changes over time as desert sites further inland.

During the latter centuries of prehistory in the Diamond Valley Lake area, local populations were increasingly affected by coastal influences. The Saratoga Springs Period (1,500–750 BP) begins with the development of bow and arrow technology, perhaps derived from the inland deserts. The lifeways of this period were abruptly interrupted by the Medieval Warm, a dramatic climatic shift that began around 1,060 BP. Inland areas were largely abandoned, except where populations could concentrate around dependable 2 Final Corona Regional Medical Center Expansion Project Archaeological and Paleontological Resources Report, prepared by ICF International, April 2013.

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water sources. The Medieval Warm ended about 575 BP, and population returned to the area during the Late Prehistoric Period (700–410 BP). The Protohistoric Period (410–180 BP) was the final period of prehistoric occupation at Diamond Valley Lake. This period was marked by the development of ceramics and Cottonwood arrow points, and the arrival of Europeans along the coast of California. (c) Historic Cultural Setting
Historical resources are buildings, structures, sites, places, or objects which are listed in or eligible for listing in the National Register of Historic Places, California Register of Historical Resources or a local register of historical resources. CEQA Guidelines, § 15064.5. Architectural, engineering, or landscape resources from the historic period such as buildings, roads, bridges, aqueducts, or agricultural properties that are determined to be historically significant or significant in architectural, engineering, scientific, economic, agricultural, educational, social, political, military, or cultural annals of California may be considered to be a historical resource, provided the determination is supported by substantial evidence in light of the whole record.

Mission Period. European settlement of California began with the founding of Mission San Diego de Alcala in 1769. The first known European exploration in Riverside County was in 1772 by a party led by Captain Pedro Fages. Four years later, Juan Bautista de Anza crossed the area en-route to Mission San Gabriel. The founding of Mission San Gabriel in 1771, San Juan Capistrano in 1776, and San Luis Rey in 1798 had a profound effect on local Native American populations. The mission fathers of Mission San Gabriel and Mission San Luis Rey gradually began colonizing the interior valleys in what is now Riverside County.

During this period, Native American groups became increasingly sedentary and learned Spanish. They provided the labor force for the mission and ranchos.

Mexican California. Mexico, including California, won independence from Spain in 1821. A decree of secularization followed in 1834. By 1846, much of the land in the region had been converted from Church- owned properties to privately held ranchos. In 1846, Governor Pio Pico issued lands including the project area to Bernardo Yorba as part of the La Sierra Rancho Land Grant.

American Period. The acquisition of California by the United States at the end of the Mexican-American War in 1848, and the discovery of gold in 1850, brought many Euro-Americans into California and promoted further cultural changes. The state developed rapidly, being admitted to statehood in 1850. However, the great influx of population was primarily limited to central California, in San Francisco and the Gold Rush region of the Sierra Nevadas. Southern California grew very slowly during this time. The process of surveying and mapping the area began in 1852, when Henry Washington and a small party of surveyors ascended the San Bernardino Mountains and established the San Bernardino Base and Meridian. (d) Archaeological Records Search and Field Assessment Results Archaeology is the recovery and study of material evidence of human life and culture of past ages. Over time, this material evidence becomes buried, fragmented or scattered or otherwise hidden from view. It is not always evident from a field survey if archaeological resources exist within a given area. Thus, the possible presence of archaeological materials must often be determined based upon secondary indicators, including the presence of geographic, vegetative, and rock features which are known or thought to be associated with

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early human life and culture, as well as knowledge of events or material evidence in the surrounding area.

Archaeological resources may include both prehistoric remains and remains dating to the historical period.

Prehistoric (or Native American) archaeological resources are physical properties resulting from human activities that predate written records and are generally identified as isolated finds or sites. Prehistoric resources can include village sites, temporary camps, lithic (stone tool) scatters, rock art, roasting pits/hearths, milling features, rock features, and burials. Historic archaeological resources can include refuse heaps, bottle dumps, ceramic scatters, privies, foundations, and burials and are generally associated in California with the Spanish Mission Period to the mid-20th century of the American Period. (i) Cultural Resource Records Search
A records search for the project area and a one-mile radius around it was conducted at the Eastern Information Center (EIC) of the California Historical Resources Information System, located at the University of California, Riverside. The EIC houses the pertinent archaeological site and survey information necessary to determine whether previously recorded cultural resources exist within the study area boundaries. The objectives of this archival research was (1) to establish the status and extent of previously recorded sites, surveys, and excavations within the project area, and (2) to note what types of sites might be expected to occur within the project area based on the existing data from archaeological sites within one mile of the project area. The search included a review of cultural resources studies and sites on file at the EIC and a review of the most up-to-date listings in the National Register of Historic Places (National Register), the California Register of Historical Resources (California Register), the California Inventory of Historic Resources, the California Historical Landmarks (CHL), the California Points of Historical Interest (CPHI), and the Historic Property Data File (HPD). In addition, historic USGS 7.5-minute, 15-minute, and 30-minute topographic quadrangle maps and General Land Office (GLO) plat maps were reviewed.

Results of the records search indicated that numerous cultural resource studies have been conducted within a one-mile radius of the project site. Eight of these studies include portions of the project area. One historic period site was previously recorded within the project area; known as Sky Ranch (33-16976); this site in Mabey Canyon consists of a small masonry shed, a metal water tank, concrete residence and aircraft hangar foundations, arroyo stone walls and bridge, and other remnant landscaping. The bridge was evaluated as eligible for the California Register as a separate property.

Eight additional cultural resources have been documented within one mile of the project site, five of which are prehistoric archaeological sites and three of which are historic-period built resources. There are no properties listed in the National Register, the California Register, the CHL, or the CPHI within a one-mile radius of the project area. In addition, no properties listed in the Historic Properties Directory match the location of the project area.

Site research confirmed documentation of historic-period mining activity within the project area. Eight adjacent mining claims were filed in 1917 by Leo Kroonen of Corona: Big 4, Black Chief, Dutch Republic, Keno, Kroonen, Little Canyon, Victor, and White Clay. However, there is indication of only minimal mining activities within the northwest portion of these claims (likely the Big 4, Little Canyon, and Victor claims) into the 1920s, and the volume of production was not large. This is consistent with the lack of discernible excavations conclusively attributable to historic period mining operations within the project area (see Field Assessment results below).

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(ii) Cultural Field Assessment
On April 10 and May 8, 2013, LSA archaeologists Riordan Goodwin and Gini Austerman conducted a reconnaissance survey of all accessible areas of the 270.9 acres that are planned for development. Due to the thick vegetation and steep topography, the surveyed areas were limited to ridge tops, accessible canyon bottoms, and road cuts.

Overall, ground visibility was poor, averaging approximately 10 percent due to obstruction from vegetation over the majority of the project surface. Mabey Canyon has been severely disturbed by agricultural activities, the development of Sky Ranch, the debris basin and associated channelization and flow-control structures of the creek in Mabey Canyon. Some of the ridge-tops have been graded for fire roads and several (recent) geological test borings.

The historic period Sky Ranch site (33-16976) was resurveyed and conditions are generally consistent with previous site record assessments. However, an unusual erosion control structure composed of an alignment of 30+ 1940s–1950s cars buried on their sides was noted on the south side of Mabey Canyon Road adjacent to the site boundary. Since its origin and date of deposition could not be determined, it was not added to the site or formally documented as a historic period feature. In addition, two adjacent isolated excavations were noted approximately 120 feet north of the project area. Although these could be mining test pits, this could not be confirmed as the excavations are nearly 0.5 mile from the nearest documented mining claim, located approximately 0.2 mile west of the project boundary.

No discernible previously undocumented cultural resources were identified within the accessible portions of the project area.

In addition, the project site includes one single-family home located within the larger 394.8-acre annexation area surrounding the site, which is located to the north of the project site (Assessor’s Parcel Number [APN] 102-320-010). Miscellaneous vacated buildings, used in conjunction with a former horse stable enterprise, are located within APN 102-320-009, adjacent to and east of the existing residence. Other uses within the surrounding annexation area, but not within the 270.9-acre project site include a nursery (APN 275-080- 021) to the north of Browning Circle and four open space parcels owned by the U.S. Wildlife Service in the southeasterly sector of the larger annexation area. None of these structures are over 45 years of age. (iii) Senate Bill 18 Consultation
The City of Corona contacted the Native American Heritage Commission (NAHC) to request a Sacred Lands File (SLF) search for the proposed General Plan Amendment (which includes the project area) in June 2013.

The NAHC responded on June 24, 2013, indicating there are no Native American traditional cultural places (TCPs) documented within the General Plan Amendment area. The NAHC also provided a list of Native American contacts with traditional lands or cultural places located in the vicinity of the project area. The City solicited formal Senate Bill (SB) 18 consultation requests from nine individuals representing eight Native American groups (the correspondence list for the individuals/groups is attached to the Supplementary Cultural Resources Assessment report included in Appendix E of this EIR) on July 16, 2013.

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At the direction of the City, LSA subsequently submitted a supplementary SLF search request to address modifications to the annexation area boundary on October 24, 2013.3 The NAHC responded on November 7 indicating that there are Native American TCPs documented within the revised study area.

Ms. Tuba Ozdil and Ms. Anna Hoover, representatives of the Pechanga Band of Luiseño Mission Indians, provided letters to the City formally requesting SB 18 consultation, that the Pechanga be involved in the entire CEQA environmental review process including notification of public hearings and scheduled approvals, that a project-specific SLF search be conducted, and receipt of all documents pertaining to this project.4 Ms. Hoover indicated that the Tribe’s records do not show any previously recorded Native American resources on the project site. However, Ms. Hoover stated the site is within the Pechanga Tribe’s traditional territory. Ms. Hoover also requested that both archaeological and Pechanga tribal monitors be present during all earthmoving activities including mass grading, brushing, grubbing and utility installation.

Ms. Hoover further asserted that the Tribe considers any resources located on the project site to be Pechanga cultural resources.

Mr. Joseph Ontiveros, a representative of the Soboba Band of Luiseño Indians, also submitted letters to the City indicating that although the site it is outside the existing reservation, the project area does fall within the bounds of Soboba’s Tribal Traditional Use Areas. Mr. Ontiveros’ stated that the Soboba Band of Luiseño Indians requests the following:

Government-to-government consultation in accordance with SB18.

That the transfer of information to the Soboba Band of Luiseno Indians regarding the progress of this project should be done as soon as new developments occur.

That the Soboba Band of Luiseno Indians continues to act as a consulting tribal entity for this project.

That Native American monitors from the Soboba Band of Luiseno Indians Cultural Resources Department be present during any ground-disturbing proceedings including surveys and archaeological testing.

That proper procedures be taken and requests of the tribe be honored. (2) Paleontological Resources
Paleontology is a branch of geology that studies the life forms of the past, especially prehistoric life forms, through the study of plant and animal fossils. Paleontological resources represent a limited, non-renewable, and impact-sensitive scientific and educational resource. As defined in this section, paleontological resources are the fossilized remains or traces of multi-cellular invertebrate and vertebrate animals and multi-cellular plants, including their imprints from a previous geologic period. Fossil remains such as bones, teeth, shells, and leaves are found in the geologic deposits (rock formations) where they were originally buried. Paleontological resources include not only the actual fossil remains, but also the collecting localities, and the geologic formations containing those localities. 3 Annexation boundary was revised to remove two parcels, APNs 275-040-004 (7.5 acres) and 275-040-005 (20.0 acres), from the proposed annexation area, for a total area reduction of 27.5 acres. 4 Ms. Tuba Ozdil’s and Mr. Joseph Ontiveros’ initial SB 18 correspondence is attached to the Supplementary Cultural Resources Assessment report included in Appendix E of this EIR. Ms. Hoover’s and Mr. Joseph Ontiveros’ correspondence is included Appendix A of this EIR within the NOP comment letters.

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(a) Geology
The Skyline Heights project is crossed by the Elsinore Fault and lies south-east of the Chino Fault (the northern branch of the Elsinore Fault). The Elsinore Fault bounds the northeast side of the Santa Ana Mountains, while the Chino Fault trends northwest and bounds the east side of the Chino (Puente) Hills. In the vicinity of the project site, the Elsinore Fault separates the Jurassic Santiago Peak Volcanics and underlying Jurassic Bedford Canyon Formation on the southwest from an upper Cretaceous through lower Tertiary sequence of sedimentary rocks that crop out southwest of the Chino Fault. The upper Cretaceous sequence includes the Baker Canyon Formation, Ladd Formation, and Williams Formation, while the lower Tertiary (Paleocene) sequence includes the Silverado Formation. Pleistocene terrace deposits are located on the larger flattened ridge tops within the project site boundaries, and overlie the deeper Tertiary and Cretaceous sequences. (b) Paleontology
Generally, the age of the Jurassic Bedford Canyon Formation is based on abundant marine fossil ammonites, pelecypods, and brachiopods. The Cretaceous age of the marine formations is also based on the ammonites, gastropods, and pelecypods that they contain. All the Mesozoic formations, which include both Jurassic- and Cretaceous-age formations, have historically produced dinosaur and reptile fossils.

The Paleocene age of the Silverado Formation is based on oysters, pelecypods, and gastropods that it contains. The earliest record of fossil Cenozoic plants comes from the coal beds in the Corona and Alberhill area of the Elsinore Trough.
(c) Paleontology Records Search and Field Assessment Results (i) Paleontological Resource Records Search
In 2006, Robert E. Reynolds, LSA Paleontologist and Senior Cultural Resource Manager, conducted a paleontological resources records search utilizing references available in local libraries and the LSA Riverside office library to determine in part the sensitivity for paleontological resources to occur in the project area. Sedimentary rocks in the Santa Ana Mountains are related to oil-bearing strata in the Los Angeles Basin and, as such, have been of special interest to geologists. Early paleontological and structural studies in the area have been followed by relatively recent updates that have been more regionally specific, correlating and clarifying earlier studies and adding to the body of data by detailed mapping and limited faunal studies. The project area is covered by geologic mapping recorded on the Corona South quadrangle, eastern Puente Hills, and on the Santa Ana Sheet.

Based on the records search results, the Santa Ana Mountains contain sediments that were deposited through the middle Mesozoic and lower Cenozoic time. The following list of formations is presented in order of deposition, the oldest first, putting the depositional history on the project site into stratigraphic perspective.

Mesozoic Era (201 million years ago)

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o Jurassic Period (201-145 million years ago). Bedford Canyon Formation (Jbm). Limestone containing ammonites and rhynchonellid brachiopods. o Cretaceous Period (145-66 million years ago). Cretaceous Volcanics (Kvem, Kvsp). Santiago Peak Volcanics are basaltic andesite, andesite dacite, and rhyolite.

Cretaceous Plutonic Complex (Kcg, Kgu, Khg, Ktgb). Granitic and gabbroic rocks making up plutons of multiple compositions.

Ladd Canyon Formation (Kl).

Holz Shale Member (Klhs). Shale and sandstone with locally abundant molluscan megafossils.

Baker Canyon Conglomerate Member (Klbc). Conglomerate and pebble sandstones, the latter containing locally abundant mollusks indicating deposition in shallow water.

Williams Formation (Kw). Conglomerates overlying the Ladd Formation.

Cenozoic Era (66-0 million years ago)5 o Tertiary Period. Silverado Formation (Tsi). These earliest Tertiary (Paleocene) rocks are interfingering marine and continental sandstones, silts, conglomerates, and clays. Non- marine sediments contain clay beds with lignite seams and fresh- and brackish-water fossil invertebrates and plants; overlying marine sediments have yielded marine invertebrates. o Quaternary Period (3-0 million years ago). Quaternary Older and Younger Alluvium (Qvo & Qo). Pleistocene older and younger alluvial deposits border the northern Santa Ana Mountains and represent fan and terrace deposits that generally drain into the Santa Ana River.

Locality References. Upper Cretaceous localities have been reported from within the project area. These marine formations contain six localities that have produced ammonites, gastropods, and pelecypods. It is highly likely that the marine mechanism that concentrated these shell beds also collected remains of vertebrate fossils.

The lower Paleocene Silverado Formation within the project site contains two known localities with oysters, pelecypods, and gastropods. It is likely that vertebrate fossils occur in shell bed concentrations. The 10 clay and lignite mines and prospects recorded among Wardlow, Mabey, and Tin Mine Canyons have good potential for fossil plants.

Dinosaurs and Mesozoic reptiles are reported from Jurassic and Cretaceous formations of the Santa Ana Mountains, which includes the project site, and thus such fossil-bearing formations may be located on-site. The review of available literature located the following records:
5 The Cenozoic Era includes the Paleogene, Neogene, and Quaternary Periods; however, the Paleogene and Neogene Periods are collectively referred to as the “Tertiary” Period, which encompasses the time period between 66 million and 3 million years before present.

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Locality B1. A string of nine vertebrae from an elasmosaurid plesiosaur is known from the Jurassic Bedford Canyon Formation of the Santa Ana Mountains. This is the oldest marine reptile from the Peninsular Range Province and also the only Jurassic specimen from the Santa Ana Mountains.

Locality L1. A hadrosaur maxilla with dentition associated with plesiosaur vertebrae is known from the Cretaceous Ladd Formation of the Santa Ana Mountains.

Locality L2. A hadrosaur vertebra is known from the Cretaceous Ladd Formation of the Santa Ana Mountains.

Locality L3. A hadrosaur tibia is known from the Cretaceous Ladd Formation of the Santa Ana Mountains.

Locality L4. The Cretaceous Ladd Formation of the Santa Ana Mountains has produced hadrosaur foot and lower limb elements as well as vertebra.

Locality L5. The turtle (Basilemys) is known from the Cretaceous Ladd Formation of the Santa Ana Mountains.

Locality L6. The Cretaceous Ladd Formation has produced additional turtle remains from another locality in the Santa Ana Mountains.

Locality W1. A dinosaur limb is known from the upper Cretaceous Williams Formation of the Santa Ana Mountains.
(ii) Paleontological Field Assessment
A field assessment of the project area was conducted by Dr. David Berry, Tina Tuttle, Jeff Vadala, and Jodi Dalton, on May 2, 4, 11, and 17, 2006, and identified two fossil localities. These localities are outcrop exposures with abundant invertebrate remains (shells of gastropods and pelecypods). It is highly likely that the currents that concentrated these shell beds also collected and concentrated the remains of vertebrate fossils.

SIR0601-LSA 06-5-03-1: Mabey Canyon. Cretaceous Ladd Formation has dense gray siliceous limestone bed with abundant mollusks, coral, bryozoa, and microfossils.

SIR0601-LSA 06-5-05-1: Chase Drive Extension (Rattlesnake Hill). Baker Canyon member of the Cretaceous Ladd Formation has a dense, blue, fine silty sandstone bed that weathers tan and contains abundant mollusks, including the gastropod Actaeonella oviformis and the pelecypods Arca sp. and Crassitella sp. This is very close to Locality 6, which produced four other genera of gastropods and pelecypods. It is highly likely that the currents that concentrated these shells also concentrated the remains of vertebrate fossils.

The Pleistocene sediments found consist of coarse, deeply-weathered fanglomerate that appears too coarse to contain fossil remains.

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b. Regulatory Framework
(1) State Level
(a) Archaeological, Historical Resources
(i) California Register of Historical Resources
Per California Public Resources Code Section 5024.1(a), the California Register of Historical Resources (California Register) is “an authoritative listing and guide to be used by state and local agencies, private groups, and citizens in identifying the existing historical resources of the state and to indicate which resources deserve to be protected, to the extent prudent and feasible, from substantial adverse change.” The criteria for eligibility for the California Register are based upon National Register of Historic Places (National Register) criteria.6 Certain resources are determined by the statute to be automatically included in the California Register, including California properties formally determined eligible for, or listed in, the National Register of Historic Places.7 To be eligible for the California Register of Historical Resources, a pre-historic or historic property must be significant at the local, state, and/or federal level under one or more of the following criteria:

1. Is associated with events that have made a significant contribution to the broad patterns of California’s history and cultural heritage;

2. Is associated with the lives of persons important in our past;

3. Embodies the distinctive characteristics of a type, period, region, or method of construction, or represents the work of an important creative individual, or possesses high artistic values; or

4. Has yielded, or may be likely to yield, information important in prehistory or history.

A resource eligible for the California Register must meet one of the criteria of significance described above and retain enough of its historic character or appearance (integrity) to be recognizable as a historical resource and to convey the reason for its significance. It is possible that a historic resource may not retain sufficient integrity to meet the criteria for listing in the National Register, but it may still be eligible for listing in the California Register.

Additionally, the California Register consists of resources that are listed automatically and those that must be nominated through an application and public hearing process. The California Register automatically includes the following resources:

California properties listed on the National Register of Historic Places and those formally Determined Eligible for the National Register of Historic Places.

California Registered Historical Landmarks from No. 770 onward. 6 California Public Resources Code § 5024.1(b). 7
California Public Resources Code § 5024.1(d).

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Those California Points of Historical Interest that have been evaluated by the California Office of Historic Preservation (OHP) and have been recommended to the State Historical Commission for inclusion on the California Register.

Other resources that may be nominated to the California Register include:

Historical resources with a significance rating of Category 3 through 5.8 Individual historical resources.

Historical resources contributing to historic districts.

Historical resources designated or listed as local landmarks, or designated under any local ordinance, such as an historic preservation overlay zone.
(ii) California Environmental Quality Act
CEQA is the principal statute governing environmental review of discretionary projects occurring in the State. CEQA requires lead agencies to determine if a proposed project would have a significant effect on archaeological resources (PRC § 21083.2.). As defined in Section 21083.2(g) a “unique” archaeological resource is an archaeological artifact, object, or site, about which it can be clearly demonstrated that without merely adding to the current body of knowledge, there is a high probability that it meets any of the following criteria:

Contains information needed to answer important scientific research questions and there is a demonstrable public interest in that information.

Has a special and particular quality such as being the oldest of its type or the best available example of its type.

Is directly associated with a scientifically recognized important prehistoric or historic event or person.

In addition, CEQA Guidelines Section 15064.5 broadens the approach to CEQA by using the term “historical resource” instead of “unique archaeological resource.” The CEQA Guidelines recognize that certain archaeological resources may also have significance. The CEQA Guidelines recognize that a historical resource includes: (1) a resource in the California Register of Historical Resources; (2) a resource included in a local register of historical resources, as defined in Public Resources Code Section 5020.1 (k) or identified as significant in a historical resource survey meeting the requirements of Public Resources Code Section 5024.1 (g); and (3) any object, building, structure, site, area, place, record, or manuscript which a lead agency determines to be historically significant or significant in the architectural, engineering, scientific, economic, agricultural, educational, social, political, military, or cultural annals of California by the lead agency, provided the lead agency’s determination is supported by substantial evidence in light of the whole record.

If a lead agency determines that an archaeological site is a historical resource, the provisions of Section 21084.1 of the Public Resources Code and Section 15064.5 of the CEQA Guidelines apply. If an archaeological 8 Those properties identified as eligible for listing in the National Register of Historic Places, the California Register of Historical Resources, and/or a local jurisdiction register.

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site does not meet the criteria for a historical resource contained in the Guidelines, then the site is to be treated in accordance with the provisions of Public Resources Code Section 21083.2, which refer to a unique archaeological resource. The Guidelines note that if an archaeological resource is neither a unique archaeological nor a historical resource, the effects of the project on those resources shall not be considered a significant effect on the environment (CEQA Guidelines § 15064.5(c)(4)). (b) Senate Bill 18
SB 18 was signed into law in September 2004, and became effective on March 1, 2005. SB 18 amended California Civil Code Section 815.3 to permit California Native American tribes recognized by the Native American Heritage Commission (NAHC) to hold conservation easements on terms mutually satisfactory to the tribe and the landowner. The term “California Native American tribe” is defined as “a federally recognized California Native American tribe or a non-federally recognized California Native American tribe that is on the contact list maintained by the NAHC.”9 The bill also requires that, prior to the adoption or amendment of a city or county’s general plan, the city or county consult with California Native American tribes for the purpose of preserving specified places, features, and objects located within the city or county’s jurisdiction. (Cal. Gov Code §65352.3) SB 18 also applies to the adoption or amendment of specific plans. This bill requires the planning agency to refer to the California Native American tribes specified by the NAHC and to provide them with opportunities for involvement. (Cal. Gov Code §65351.)
(c) California Health and Safety Code
The California Health and Safety Code Section 7050.5 states that if human remains are discovered on site, no further disturbance shall occur until the County Coroner has made a determination of origin and disposition.

If the Coroner determines that the remains are not subject to his or her authority and if the Coroner recognizes the human remains to be those of a Native American, or has reason to believe that they are those of a Native American, he or she shall contact, by telephone within 24 hours, the NAHC. This regulation is applicable to any project where ground disturbance would occur. (d) Paleontological Resources
Paleontological resources are also afforded protection by environmental legislation set forth under CEQA.

Appendix G (part V) of the CEQA Guidelines provides guidance relative to significant impacts on paleontological resources, stating that “a project will normally result in a significant impact on the environment if it will …disrupt or adversely affect a paleontologic resource or site or unique geologic feature, except as part of a scientific study.” Section 5097.5 of the PRC specifies that any unauthorized removal of paleontological remains is a misdemeanor. Further, the California Penal Code Section 622.5 sets the penalties for damage or removal of paleontological resources. 9 SB18 Tribal Consultation, State of California Tribal Consultation Guidelines Supplement to General Plan Guidelines, April 15, 2005.

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(2) Local
(a) City of Corona
The Historic Resources Element of the City’s General Plan includes policies regarding the conservation and management of archaeological and paleontological resources. The project’s consistency with the applicable policies is discussed in the impact analysis below.

2. ENVIRONMENTAL IMPACTS
a. Methodology
(1) Historic Resources
As described above, to determine the presence of any known historic resources on the project site and within a one-mile radius of the project site, an extensive records search and pedestrian survey was conducted. The search included a review of cultural resources studies and sites on file at the EIC and a review of the most up-to-date listings in the National Register, California Register, California Inventory of Historic Resources, CHL, CPHI, and HPD. In addition, historic USGS maps were reviewed.

The survey process undertaken for purposes of this evaluation was conducted per OHP instructions, which gives a 45-year threshold for surveying properties for significance. Those properties that were of post-1969 construction (under 45 years of age) were not documented in the project survey unless they exhibited potentially “exceptional” importance.
(2) Archaeological and Paleontological Resources
LSA conducted a literature and records search of the project area at the EIC located at the University of California Riverside and to determine if archaeological resources are located within the project area. The search included a review of all available cultural resource surveys and site records within the project area and within a one-mile radius. In addition, a field survey of the project site was conducted to observe the presence of any visible archaeological resources on the site.

With regard to paleontological resources, LSA reviewed geological and paleontological literature and the geological maps of Corona and its surroundings. The geologic context was analyzed, and the paleontological sensitivity of sediments underlying the project area was evaluated based on the past finds in the region.

Impacts on cultural resources from the project were evaluated by determining whether ground disturbance activities could affect areas that could contain any resources. Impacts on paleontological resources were evaluated similar to the way in which impacts to buried archaeological resources were evaluated, that is by determining whether ground disturbance activities would affect areas that could contain any a unique paleontological resource or site or unique geologic feature. b. Thresholds of Significance
Appendix G of the CEQA Guidelines (the Initial Study Environmental Checklist form) and the City’s Initial Study Checklist include questions relating to cultural resources that are utilized as the thresholds of

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significance in this section (Thresholds 1-5). Accordingly, the project may create a significant environmental impact if it would:

Threshold 1: Cause a substantial adverse change in the significance of a historical resource as defined in Section 15064.5 (refer to Impact Statement 4.D-1);
Threshold 2: Cause a substantial adverse change in the significance of an archaeological resource pursuant to Section 15064.5 (refer to Impact Statement 4.D-2);
Threshold 3: Directly or indirectly destroy a unique paleontological resource or site or unique geologic feature (refer to Impact Statement 4.D-3);
Threshold 4: Disturb any human remains, including those interred outside of formal cemeteries (refer to Impact Statement 4.D-4); and
Threshold 5: Conflict with an applicable plan, policy or regulation adopted for the purposes of avoiding or mitigating physical impacts associated with cultural resources (refer to Impact Statement

4.D-5).
c. Project Design Features
The project does not include any Project Design Features (PDFs) specific to cultural resources. d. Analysis of Project Impacts
(1) Historic Resources
Threshold 1: Cause a substantial adverse change in the significance of a historical resource as defined in Section 15064.5.

Impact 4.D-1 No historic resources are located on the project site. As such, there is no potential for the project to cause a substantial adverse change in the significance of a historical resource as defined in Section 15064.5 of the CEQA Guidelines. No impact would occur in this regard. According to the records search, no previously recorded historical resources were identified within the project site and no new historical resources within the project site were identified during the pedestrian survey. Further, the single-family residence and nursery within the annexation area are not 45 years of age and do not otherwise meet the criteria for listing in the California Register and do not qualify as historical resources as defined in Section 15064.5 of the CEQA Guidelines. As a result, the project would not cause a substantial adverse change in the significance of a known historical resource as defined in CEQA Section 15064.5. No impact would occur in this regard.

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(2) Archaeological Resources
Threshold 2: Cause a substantial adverse change in the significance of an archaeological resource pursuant to Section 15064.5.

Impact 4.D-2 Implementation of the project would not cause a substantial adverse change in the significance of a known archaeological resource pursuant to Section 15064.5 of the CEQA Guidelines.

However, there is potential for the project to impact previously undiscovered archaeological resources during construction activities associated with the project. This potentially significant impact would be reduced to a less than significant level with implementation of the prescribed mitigation measure. No archaeological or Native American resources were identified within the project development footprint area in prior surveys. However, several resources do exist within a one-mile radius of the site. This suggests that the project area has a low to moderate potential to encompass historical period archaeological or prehistoric archaeological resources, despite the minimal historic-period mining activity within the project area. Current project plans do not include impacts to the Sky Ranch site’s (APN 275-040-015) bridge that was evaluated as eligible for the California Register. In the event project plans change to include potential impacts to the bridge, the impacts would need to be evaluated in a supplemental study.

As part of the Native American Consultation conducted for the project, letters were sent to the eight Native American Tribes provided by the NAHC in July and October 2013. The letters included a brief project description and asked that the tribes to contact the City with input regarding the presence of cultural resources in the project area. Two tribes, the Pechanga Band of Luiseño Indians and Soboba Band of Luiseño Indians (Tribes) requested further consultation and future updates in regards to the project. The Tribes requested that Native American monitors be present on-site during any ground-disturbing activities, including surveys and archaeological testing.

Despite the lack of known resources within the site, correspondence from representatives of the Pechanga and Soboba Bands of Luiseño Indians indicates the site has the potential to support previously undiscovered Native American resources. Of particular relevance, Ms. Hoover of the Pechanga Band of Luiseño Mission Indians, states that as the site includes dense vegetation, unidentified cultural resources may exist on the site. She states that the location of the site at the base of the Cleveland National Forest/Santa Ana Mountains likely contains a deep accumulation of alluvium which would have covered Luiseño habitations and villages over time. Additionally, she states that there are several drainages that flow from the mountains that would have supplied fresh water to any inhabitants in the area. Thus, the potential for impacting surface and subsurface cultural resources is high. In light of these considerations, it is concluded that unknown significant Native American cultural resources could be unearthed during project excavation activities. The project would involve surface disturbance and grading, and would require trenching for utilities. Grading and trenching as well as other construction ground-disturbing actions have the potential to disturb and destroy cultural resources. Disturbance of significant cultural resources would result in a significant adverse impact. Thus, Mitigation Measure CR-1 is prescribed in the event that unknown cultural materials are discovered during construction. Mitigation Measure CR-1 also includes provisions for Native American monitors from affected Tribes to observe all project-related grading activities, and the implementation of a Treatment Agreement between affected Tribes. With the implementation of Mitigation Measure CR-1, potentially significant impacts to unknown resources would be reduced to a less than significant level.

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Further, given that the City has fulfilled its obligations for Native American Consultation pursuant to SB18 and will continue to work with the Tribes to facilitate monitoring during future site development per Mitigation Measure CR-1 to ensure proper treatment of newly discovered resources, impacts to Native American resources would be less than significant with mitigation. (3) Paleontological Resources
Threshold 3: Directly or indirectly destroy a unique paleontological resource or site or unique geologic feature.

Impact 4.D-3 Implementation of the project could directly impact paleontological resources during construction activities. This potentially significant impact would be reduced to a less than significant level with implementation of the prescribed mitigation measures.

The paleontological resources assessments for the project found that the fossiliferous Upper Cretaceous Ladd Canyon Formation and Upper Cretaceous Williams Formation occur on the project site. In addition, the fossiliferous Paleocene Silverado Formation occurs within the project boundaries. These three formations have potential to contain significant, nonrenewable paleontological resources. Construction for the project would include grading and excavation for the development of housing pads, access roads, sewers, drains, culverts, and utility-related infrastructure that could impact paleontological resources in these three formations. Disturbance to paleontological resources could result in a potentially significant impact. Thus, Mitigation Measures CR-2 to CR-4 have been prescribed to address this potentially significant impact. The mitigation measures require preparation of a paleontological resource impact mitigation program (PRIMP) to be implemented during construction activities for the project. The PRIMP would provide appropriate treatment measures for paleontological resources potentially impacted by the project. With implementation of these mitigation measures, potentially significant impacts to paleontological resources would be reduced to a less than significant level.
(4) Human Remains
Threshold 4: Disturb any human remains, including those interred outside of formal cemeteries.

Impact 4.D-4 In the unlikely event human remains are discovered during grading or construction activities within the project site, compliance with State law (Health and Safety Code § 7050.5) (HSC § 7050.5) would be required and would mitigate for potential impacts to human remains.

Therefore, impacts related to the discovery of buried human remains would be less than significant and no mitigation is necessary.

The project site is not a formal cemetery and is not adjacent to a formal cemetery. The project site is not known to contain human remains interred outside formal cemeteries, nor is it known to be located on a burial ground or reported to have yielded human remains. In the unlikely event human remains are discovered during grading or construction activities within the project site, compliance with State law (Health and Safety Code § 7050.5) (HSC § 7050.5) would be required. These requirements are imposed on any construction activity in which human remains are detected, and include the following provisions:

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There shall be no further excavation or disturbance of the site or any nearby area reasonably suspected to overlie adjacent human remains until:
o The coroner of the county in which the remains are discovered must be contacted to determine that no investigation of the cause of death is required; and o If the coroner determines the remains to be Native American:

The coroner shall contact the Native American Heritage Commission within 24 hours.

The NAHC shall identify the person or persons it believes to be the most likely descended from the deceased Native American.

The most likely descendant may make recommendations to the landowner or the person responsible for the excavation work, for means of treating or disposing of, with appropriate dignity, the human remains and any associated grave goods as provided in Public Resources Code § 5097.98 (PRC § 5097.98), or Where the following conditions occur, the landowner or his authorized representative shall rebury the Native American human remains and associated grave goods with appropriate dignity on the property in a location not subject to further and future subsurface disturbance pursuant to PRC § 5097.98(e).
o The NAHC is unable to identify a most likely descendant. o The most likely descendant is identified by the NAHC, fails to make a recommendation within 48 hours of being granted access to the site; or
o The landowner or his authorized representative rejects the recommendation of the descendant, and mediation by the NAHC fails to provide measures acceptable to the landowner.

Adherence to provisions of Health and Safety Code § 7050.5 is required of all development projects.

Compliance with existing state law sufficiently mitigates for potential impacts to human remains. Therefore, impacts related to the discovery of buried human remains would be less than significant and no mitigation is necessary.
(5) Consistency With Regulatory Framework
Threshold 5: Conflict with an applicable plan, policy or regulation adopted for the purposes of avoiding or mitigating physical impacts associated with cultural resources.

Impact 4.D-5 Implementation of the project would not conflict with an applicable plan, policy or regulation adopted for the purposes of avoiding or mitigating physical impacts associated with cultural resources. This impact is considered less than significant.

The project would comply with all applicable State and federal regulations regarding cultural resources as described above, and therefore no significant impacts regarding conflicts with such laws would result from project implementation. Furthermore, the project would not conflict with applicable policies contained in the City’s General Plan regarding cultural resources, as discussed below in Table 4.D-1, General Plan Consistency Analysis. As discussed in Table 4.D-1, the project would not conflict with the applicable policies of the City’s General Plan and as such impacts in this regard would be less than significant.

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Table 4.D-1
General Plan Consistency Analysis
Goals and Policies Consistency
Community Development – Historic Resources
Goal 4.3 – Recognize the importance of
archeological and paleontological resources and
ensure the identification and protection of those
resources within the City of Corona.

Consistent. No archaeological or Native American resources were identified within the project development footprint area in prior surveys. However, several resources do exist within a 1- mile radius of the site. In addition, correspondence with Tribes in the area indicate cultural resources may be located within the project boundaries. This suggests that the project area has a low to moderate potential to encompass historical period
archaeological or prehistoric archaeological resources, despite the minimal historic-period mining activity within the project area. Nonetheless, significant buried cultural resources could occur within the project area and it is possible these materials could be unearthed during project excavation activities.

Furthermore, the project site is located on fossiliferous formations known to have produced fossils. The project would implement mitigation measures to appropriately treat
archaeological and paleontological resources should they be discovered during project construction activities.

Policy 4.3.3 – Archaeological resources found
prior to or during construction shall be
evaluated by a qualified archaeologist, and
appropriate mitigation measures applied,
pursuant to Section 21083.2 of CEQA, before the
resumption of development activities. Any
measures applied shall include the preparation
of a report meeting professional standards,
which shall be submitted to the appropriate
CHRIS information center.

Consistent. In the event of an archaeological discovery, the project would implement Mitigation Measures CR-1. This would ensure that all earthmoving activity within and around the immediate discovery area would be diverted until a qualified archaeologist could assess the nature and significance of the find and, if necessary, develop appropriate treatment measures.

Treatment measures typically include developing avoidance strategies, capping with fill material, or mitigating impacts through data recovery programs such as excavation or detailed documentation.

Policy 4.3.4 – Any project that involves earth- disturbing within previously undisturbed soils in an area determined to be archaeologically or
culturally sensitive, shall require evaluation of
the site by a qualified archaeologist retained by
the project applicant. The applicant shall
implement the recommendations of
archaeologist, subject to the approval of the City
Planning Department.

Consistent. LSA Associates, Inc. prepared project-specific archaeological and paleontological resources assessment reports, which include recommendations for the discovery, handling, and treatment of any resources encountered during site grading activities.

Policy 4.3.5 – Any project that involves earth- disturbing activities in previously undisturbed soils that have been determined to be
archaeologically or culturally sensitive shall
require consultation by the applicant with
interested federally recognized American Indian
Tribe(s) that have a traditional cultural
affiliation with the project area and/or the
resources affected by the project, for the
purposes of determining archaeological and
cultural resources impacts and creating
appropriate mitigation to address such impacts.

Consistent. The project applicant has conducted tribal
consultation in accordance with this policy, and formal government-to-government consultation with the City of Corona has also been initiated in accordance with SB18. As required by Mitigation Measure CR-1 below, tribal monitors would be present for all site grading activities.

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Goals and Policies Consistency
The applicant shall also arrange for monitoring
earth-disturbing activities by interested
federally recognized American Indian Tribe(s)
that have a traditional cultural affiliation with
the project area and/or the resources affected
by the project, if requested.

Policy 4.3.6 – Any project that involves earth- disturbing activities in soil or rock units known or reasonably suspected to be fossil-bearing
shall require monitoring by a qualified
paleontologist retained by the project applicant
for the duration of excavation or trenching.

Consistent. As provided by Mitigation Measure CR-2 below, a qualified paleontological monitor would be present for all site grading activities as determined appropriate by the PRIMP.

Policy 4.3.7 – Paleontological resources found
prior to or during construction shall be
evaluated by a qualified paleontologist, and
appropriate mitigation measures applied,
pursuant to Section 21083.2 of CEQA, before the
resumption of development activities. Any
measures applied shall include the preparation
of a report meeting professional standards,
which shall be submitted to the Riverside
County Museum of Natural History.

Consistent. Mitigation Measures CR-2 to CR-4 address potential impacts to paleontological resources. Per the prescribed mitigation measures, a qualified vertebrate paleontologist would be retained by the City or project proponent to determine areas that would require paleontological monitoring during initial ground disturbance. Collected fossils, if any, would be transported to a paleontological laboratory for processing where they would be prepared to the point of curation, identified by qualified experts, listed in a database to facilitate analysis, and deposited in a designated paleontological curation. Following analysis, a report of findings with an appended itemized inventory of specimens would be prepared. The report and inventory, when submitted to the appropriate lead agency along with confirmation of the curation of recovered specimens into a public, non-profit institution with a research interest in the materials, would signify completion of the program to mitigate impacts on paleontological resources.

Policy 4.3.8 – In the event of the discovery of a
burial, human bone, or suspected human bone,
all excavation or grading in the vicinity of the
find shall halt immediately and the area of the
find shall be protected and the project applicant
immediately shall notify the Riverside County
Coroner of the find and comply with the
provisions of the California Health and Safety
Code Section 7050.5, including P.R.C. Section
5097.98, if applicable. In the event that human
remains are determined to be Native American
human remains the applicant shall consult with
the Most Likely Descendent (MLD) to determine
the appropriate treatment for the Native
American human remains.

Consistent. Proposed grading activities would be carried out in accordance with applicable laws regarding cultural resources, including the treatment of human remains and notification of tribal organizations, as applicable.

Source: PCR Services Corporation, 2014.

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3. CUMULATIVE IMPACTS
The cumulative area for cultural resources is the regional tribal areas for the traditional cultural territories of the Gabrielino/Tongva Indians, Luiseño Indians, and possibly the Cahuilla Indians. The cumulative are, also includes the City of Corona. As described above, the project would result in no impacts to historic resources; therefore, the project does not have the potential to contribute to cumulative impacts regarding historic resources. Implementation of the project would include mitigation measures to identify, recover, and/or record any cultural and/or paleontological resource that may occur within the limits of the project site. Potential impacts associated with human remains would be reduced to a less than significant level through adherence to existing State law. There are no projects that would, in combination with the project, result in any significant cumulative impacts on archaeological, or paleontological resources, or in impacts to human remains. Like the project, any other projects within the City or within the regional tribal areas would be required to adhere to similar mitigation measures that would reduce the potential for any individual or cumulative impacts. On a cumulative level, data recovered from a site, combined with data from other sites in the region, would allow for the examination and evaluation of the diversity of human activities in the region. Therefore, the project would have less than significant cumulative impacts associated with cultural resources.

4. MITIGATION MEASURES
Based on the analysis above, the project could result in a potentially significant impact to archaeological/Native American and paleontological resources. Therefore, the following mitigation measures are recommended:

Mitigation Measure CR-1: In the event that archaeological materials are discovered during construction, all earth-moving activity within and around the immediate discovery area shall be diverted until a qualified archaeologist can assess the nature and significance of the find, and, if necessary, develop appropriate treatment measures. Treatment measures typically include development of avoidance strategies, capping with fill material, or mitigation of impacts through data recovery programs such as excavation or detailed documentation. If during cultural resources monitoring the qualified archaeologist determines that the sediments being excavated are previously disturbed or unlikely to contain significant cultural materials, the qualified archaeologist can specify that monitoring be reduced or eliminated.

Native American monitors from affected Tribes shall observe all project-related grading activities, and the treatment of any recovered artifacts shall be carried out in accordance with the provisions of a Treatment Agreement between affected Tribes. The Treatment Agreement shall be executed by the consulting Tribes prior to the issuance of grading permits for each construction phase. All cultural materials that are collected during the grading monitoring program and from any previous archaeological studies or excavations on the project site shall be curated according to the current professional repository standards. The collections and associated records shall be transferred, including title, to an appropriate curation facility which meets the standards set forth in 36 CFR Part 79 for federal repositories. All sacred sites, should they be encountered within the project area, shall be avoided and preserved as the preferred mitigation.

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If changes are made to the project footprint to include earth-moving activities in areas not previously studied, additional archaeological investigations shall be required.

Mitigation Measure CR-2: Prior to issuance of any grading permit, the Applicant shall retain a qualified vertebrate to develop a paleontological resource impact mitigation program (PRIMP) for excavations into the Upper Cretaceous Ladd Canyon Formation, the Upper Cretaceous Williams Formation, and Paleocene Silverado Formations. A qualified vertebrate paleontologist is defined as a paleontologist meeting the criteria established by the Society for Vertebrate Paleontology. The qualified vertebrate paleontologist shall conduct a pre-construction field assessment to locate fossils at surface exposures. The qualified vertebrate paleontologist shall supervise a paleontological monitor who shall be present at such times as required by the paleontologist during construction excavations into the fossiliferous formations mentioned above. Monitoring shall consist of visually inspecting fresh exposures of rock for larger fossil remains and, where appropriate, collecting wet or dry screened sediment samples of promising horizons for smaller fossil remains. The frequency of monitoring shall be determined by the paleontologist and shall be based on the rate of excavation and grading activities, the materials being excavated, and the depth of excavation, and if found, the abundance and type of fossils encountered. If resources are located, monitoring hours shall be increased as needed.

Mitigation Measure CR-3: If a potential fossil is found, the qualified vertebrate paleontologist or paleontological monitor shall be allowed to temporarily divert or redirect grading and excavation activities in the area of the exposed fossil, as determined appropriate by the monitor, to assess the significance of the find and, if necessary, develop appropriate treatment measures. Treatment measures may include avoidance or preservation in place, if feasible. If preservation or avoidance of the resource is not feasible, then the resource shall be removed from its location. Removal activities may consist of the relatively rapid removal of small isolated fossils from an active cut, to hand-quarrying of larger fossils over several hours, to excavations of large fossils or large numbers of smaller fossils from a bone bed over several days. These activities may include the assistance of the grading and excavation contractor’s equipment to facilitate removal.

Any fossils encountered and recovered shall be prepared to the point of identification and catalogued before they are donated to their final repository. Any fossils collected shall be donated to a public, non-profit institution with a research interest in the materials, such as the Natural History Museum of Los Angeles County, San Bernardino County Museum, the John D. Cooper Archaeological and Paleontological Curation Center at the California State University, Fullerton, or Western Science Center in Hemet, California. Accompanying notes, maps, and photographs shall also be filed at the repository.

Mitigation Measure CR-4: Prior to the release of the grading bond, the paleontologist shall prepare a report summarizing the results of the monitoring and salvaging efforts, the methodology used in these efforts, as well as a description of the fossils collected and their significance. The report shall be submitted by the Applicant to the Community Development Director or his/her designee for approval. In addition, the report shall be submitted to at least one of the repositories mentioned in Mitigation Measure CR-3 and other appropriate or concerned agencies to signify the satisfactory completion of the project and required mitigation measures.

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5. LEVEL OF SIGNIFICANCE AFTER MITIGATION
With compliance with applicable requirements regarding cultural resources and with the implementation of the above mitigation measures, potentially significant impacts to cultural resources would be reduced to a less than significant level.

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4. ENVIRONMENTAL IMPACT ANALYSIS
E. GEOLOGY AND SOILS

INTRODUCTION
This section describes existing conditions and the regulatory framework associated with geology and soils and analyzes the potential impacts of the project regarding fault rupture, seismic hazards, ground shaking, liquefaction, soil erosion or the loss of topsoil, expansive soils, and landform/landslide in the City of Corona and in the vicinity of the site. Information in this section is based on information and findings obtained in the Preliminary Geotechnical Investigation and Grading Plan (herein referred to as the Geotechnical Report), for Tentative Tract Map No. 36544, prepared by Ginter and Associates, Inc. in April 2014. The Geotechnical Report is included in Appendix F of this Draft EIR.

1. ENVIRONMENTAL SETTING
a. Existing Conditions
(1) Regional Geology
The site is located on the northeastern slope the Temescal Canyon area of the Santa Ana Mountains near their boundary with Temescal Canyon (see Plate I; Elsinore-Chino Trough, of Appendix F, Geotechnical Report, of this Draft EIR). The Santa Ana Mountains are one of many northwest-trending Southern California ranges separated by broad valleys within the Peninsular Ranges Geomorphic (and structural) Province of Southern California. The province extends from the Transverse Ranges on the north to Baja California on the south.

The Santa Ana Mountains have a Jurassic and Cretaceous metamorphic and igneous core on which Cretaceous through Pliocene marine and non-marine rocks have been deposited. Along the northeast flank of the mountains, the Cretaceous and Tertiary rocks were strongly tilted and folded during later regional deformation (see Plate IV of the Geotechnical Report). Pleistocene to modern sediments derived mainly from the upper reaches of the Santa Ana Mountains locally mantle those rocks. These sediments are mainly elevated Pleistocene river terrace and alluvial fan deposits and Holocene fans on the floors of Temescal and Santa Ana Canyons and consisting of modern alluvium in incised drainages and toe-slope colluvium. The highlands of the Peninsular Ranges are formed in an eroded granitic/metamorphic basement complex, and the lowlands consist of sediment-filled basins. Northwest trending “main” ridges and “spur” ridges with steep sides dominate the geomorphology. Low-order drainages feed three high-order drainages that extend over large areas of the northeastern Santa Ana Mountains. These high-order drainages are, from north to south, Mabey, Kroonen and Tin Mine Canyons (see Plate I in the Geotechnical Report in Appendix F of this Draft EIR). Both following and breaching the local geologic structures and lithologies, these major drainage are commonly “v”-shaped in their upper and middle reaches, where incised into bedrock and flat in their lower reaches.

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The northwest-trending Peninsular Ranges blocks parallel regional continental borderland faults that extend from the Mojave Desert in the east to the Channel Islands on the west. These fault zones are typically exhibit right-lateral strike-slip with associated reverse and normal dip-slip components. The approximately 150- mile long Whittier-Elsinore Fault Zone) that parallels the northeast Santa Ana Mountains is a classic example.
(2) Site Conditions
The project site is located at the mouths of Mabey Canyon, Tin Mine, and Kroonen Canyons immediately to the east of the Cleveland National Forest. The site consists of two geographic sections separated by Mabey Canyon. To the north of Mabey Canyon, the area is in an almost natural state and characterized by steep topography with a thin soil mantle. Remnants of exploration roads associated with clay mining occurred in the Temescal Canyon area from the early 1900’s are evident. However, no large-scale mining operations appear to have occurred in this area. The area to the north of Mabey Canyon generally consists of steep- sided northeast trending “main” ridges with similar steep-sided “spur” ridges on the northeastern flank of the Santa Ana Mountains. Side-slope ratios vary from 2:1 to 1:1 with local gentler and steeper sections.

These configurations result in v-shaped canyons and narrow, spine-like ridges. Also in this area, three low- order canyons drain northwesterly into Wardlow Canyon and the one drains the center of this area into high-order Mabey Canyon to the south. These major drainages are v-shaped in their upper and middle reaches, where incised into bedrock, and flat in their lower reaches. The Mabey Canyon drainage flows into a large flood control basin near its mouth (see Plate I in the Geotechnical Report). The basin intercepts flow and directs flow northeast via lined channels into Temescal Canyon and eventually, the Santa Ana River system.

The area to the south of Mabey Canyon was subjected to clay prospecting and mining in the early 1900’s.

One successful clay prospect was the McKnight Clay Mine southeast adjacent to the area (see Plate V in the Geotechnical Report), which now serves as a tree nursery. Other poorly-preserved and undeveloped prospects and related access roads are scattered over the site. For example, an exploration trench (Pacific Soils Engineering, Inc. (PSE), 2005) encountered a small mine entrance on-site. As with the northern portion of the site, northwest trending ridges and V-shaped canyons dominate the geomorphology. (a) Stratigraphy
Cretaceous Trabuco Formation
The highland portions of the project site are underlain by resistant Cretaceous and Paleocene sedimentary rocks that are locally mantled by older Pleistocene alluvial "terrace" deposits. The lowland surfaces support mainly Holocene alluvial channel and fan deposits (see Figures 1 through 7 in the Geotechnical Report). The Cretaceous Trabuco Formation (Kt) is mainly brown, weakly to moderately lithified cobble to boulder conglomerate, marked by occasional lenses and beds of distinctive maroon silty conglomerate that crops out in the southwest corner of the site). Clasts are mainly metamorphic, igneous and volcanic fragments that are usually more weathered than clasts within the overlying Ladd Formation. Following the regional structural grain, this formation extends from northwest to southeast south of Tin Mine Canyon. Trenches placed south of the project site (see Plate II in the Geotechnical Report) exposed distinct Trabuco "maroon beds” on the south flank of Tin Mine Canyon, thereby documenting formational continuity across Tin Mine Canyon. This contradicts previous geologic maps (Gray, 1961; Weber, 1977; Gray et al., 2002) that depict the formation “fault-truncated” north of the canyon. The Trabuco Formation grades upward into the Cretaceous Ladd

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Formation. The contact between the two formations is thus arbitrary and herein taken to be the top of the uppermost Trabuco "maroon bed”.1
Cretaceous Ladd Formation
Two formal members, the Baker Canyon Conglomerate and Holz Shale, of the Cretaceous Ladd Formation Conglomerate (Klc) crop-out northwest and south of Kroonen Canyon (see Figures 1 through 7 in the Geotechnical Report). These are were readily identifiable in trenches and, locally identifiable in outcroppings. In contrast, massive conglomerates and sandstones of undifferentiated Ladd Formation are north and east of the canyon, which may also encompass Williams Formation sandstone (see Figures 2, 4 and 5 of the Geotechnical Report). Clearly identifiable and mappable Williams Formation does crop out in the northern part of the site, northwest of Mabey Canyon.2 The Baker Canyon Conglomerate (Klbe) is located at and near the project site. This formation consists of thick-bedded to massive pebble and cobble conglomerate interspersed with buff to gray arkosic to lithic marine sandstone. The lower part of the formation consists mainly of distinctly bedded, volcanic and metamorphic cobble conglomerate. Distinctly inter-bedded buff conglomerate and buff to gray thick-bedded sandstone characterize the upper part of the formation exposed onsite. This unit is generally well-indurated (cemented) below a weathered halo and therefore, supports steep anti-dip and dip slopes, and is a major "ridge former". The Baker Canyon Conglomerate is conformable with, and grades into, both the underlying Trabuco Formation and the overlying Holz Shale Member of the Ladd Formation. The transition zone, based varies from about 50 to about 100-feet thick. 3 Holz Shale (Klh), weathered shale, claystone, siltstone and silty sandstone, forms a narrow V-shaped band typified by subdued, linear topography in the western part of the project site (see Figures 4 and 6 in the Geotechnical Report). The outcrop pattern describes a regional, closed, locally overturned, southeast- plunging syncline (see Plate IV in the Geotechnical Report). This formation unit is locally fossiliferous, gray to bluish gray where fresh and gray to yellowish brown where weathered. Generally, the unit is thin-bedded and has well-developed bedding plane parting. Calcareous concretions up to three feet in diameter occur throughout the Holz Shale. Despite the presence of concretions, the unit is poorly resistant to weathering and forms subdued topography relative to the underlying Cretaceous conglomerate and the overlying Tertiary sandstone. Where observed during prior geologic investigations of the area, the Holz Shale is usually fractured (squeezed) and is replete with small-scale "flow" folds symptomatic of plastic deformation.

This contrasts with the brittle behavior of the overlying and underlying Silverado Formation and Baker Conglomerate where faults, fractures and similar brittle deformation predominate. Local ridges of Baker Canyon Conglomerate and topographic lows carved in previously unidentified Holz Shale. The absence of Tertiary Silverado and the presence of "Cretaceous-against-Cretaceous" relationships suggest limited structural relief and stratigraphic separation. Accordingly, large-scale fault displacements are therefore, not necessary to explain local bedrock geometry and distribution.4 1 Ginter and Associates, Inc., Preliminary Geotechnical Investigation and Grading Plan, April 2014, page 15. 2 Op. Cit, page 16. 3
Ibid. 4
Op. Cit., pages 16-17.

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A large lithesome of well-indurated conglomerate of the Ladd Formation interspersed with scattered sandstone beds underlies most of the area south of Mabey Canyon and north of Kroonen Canyon. Similar to the Baker Conglomerate, except that it is typically massive with few plane partings, the geological structural pattern is not particularly well-defined. Refractive seismic lines suggest that at depth, this unit is well lithified.5 The local Cretaceous Williams Formation (Kw) formation comprises abundant, granitoid cobbles and boulders with local absence of stratification. The granitoid clasts differentiate this formation from the Ladd Formation that supports mainly volcanic and metamorphic cobbles. This formation underlies the northern part of the study property and possibly crops out along the ridge northwest of Kroonen Canyon.

Well-cemented fossiliferous beds of the Paleocene Silverado Formation (Tsi) are scattered throughout the on-site Silverado Formation. Non-marine and locally marine light buff, to light gray, to yellow silty sandstone, intercalated red and gray/white claystone and scattered cobble conglomerate characterize the formation. Bedding varies from thin to massive and is usually identifiable in natural and anthropic outcrops.

The sandstone is moderately resistant. The limy fossiliferous beds are very resistant and the claystones are poorly resistant. Consequently, differential erosion of the red clay beds imparts steep, linear strike-parallel ridges and ravines. Hard limy beds form particularly evident spines along some ridgelines. A few to a few tens of feet thick, sedimentary clays derived from nearby clay-rich saprolites that formed on an erosion surface prior to deposition of the remainder of the Silverado Formation. These beds, which may be the lateral equivalent of the Claymont clay bed, were mined for clay at the McKnight Clay Mine and at the Kroonen Clay Prospect. One particular limy, fossiliferous bed is depicted in the Geotechnical Report (Appendix F of this Draft EIR), Figures 6 and 7 (geologic map), along with two smaller, discontinuous ones.

Composed of Ostrea, sp. and other mollusks, this bed is traceable from the northeast property line westward to near the south-center where it is tightly folded into a synform, as attested to by V-shaped outcrop pattern.

The red and limy beds are readily identifiable and often laterally continuous and are thus, excellent local and regional key beds to determine the presence or absence of bedrock faults.6 (b) Alluvial Deposits
Local Quaternary alluvium consists of: (1) Older (Pleistocene) alluvial fan and "terrace" deposits elevated above the modern (Holocene) drainage; and (2) Holocene alluvium occupying the floors of active channels and swales, where detritus is seasonally transported, deposited and eroded. Based on prior studies of the region, underlying alluvial deposits were inferred to be up to 200,000 to 300,000 years old. Both soil- stratigraphic and morpho-stratigraphic hierarchies are useful to assess the age of the Quaternary deposits in the Corona area. A greater than 18-foot-thick cap of older alluvium occurs as an elevated "terrace" along the south side of Mabey Canyon (the "Mabey Fanglomerate”). Trenches in the area have also exposed more than 20 feet of older alluvium (the Kroonen Deposit) near the head of a major tributary to Kroonen Canyon. The Mabey Faglomerate is more than 18 feet thick where it underlies an extensive Pleistocene terrace above Mabey Canyon (see Figure 2 in the Geotechnical Report). These deposits are typically poorly sorted, arkosic to lithic, subanglular to well-rounded sand and gravels, replete with ubiquitous cut-and-fill structures. Also common, are well-sorted, current-laminated sands and moderately sorted basal cobble and boulder beds.

Regionally, this deposit occurs at elevations similar to other high elevation fanglomerates along the east 5 Op. Cit., page 17. 6
Op. Cit, page 18.

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flank of the Santa Ana Mountains adjacent to or near the Whittier-Elsinore Fault Zone; namely, at least several tens of feet above active Temescal Canyon drainages and alluvial fans. Uplift along the Eagle Fault and associated "beheading" of the proximal parts of the fans by erosion has now both cut off these fans from their original source areas and elevated them above Temescal Canyon.7 Another deposit of older alluvium, overlying the Ladd Formation in depositional contact, occurs near the head of Kroonen Canyon (see Figure 4 of the Geotechnical Report). The depth to bedrock is approximately 35 feet at this location. The Kroonen deposits are mainly sand, silty sand and clayey sand. Abundant gravel typical of most regionally extensive alluvial fan deposits is absent, although occasional gravel stringers and "stone lines" are scattered throughout the section.8
(3) Groundwater
Perched groundwater was encountered during prior geologic investigation (borings) at 39 feet below ground surface. No groundwater was encountered during prior fault investigations. Groundwater could potentially be trapped seasonally along alluvium/bedrock contacts and bedrock fractures. Weber (1977) estimated the regional groundwater surface to be 100 ft. to 200 ft. below the existing ground surface.9 Groundwater conditions are described in greater detail in Section 4.H, Hydrology and Water Quality, of this Draft EIR.
(4) Seismic Hazards
The site is located in tectonically active Southern California. Figure 4.E-1, Regional Fault Map of Southern California, shows the site in relation to regional faults. The type and magnitude of seismic hazards affecting a site are dependent on the distance to the causative fault, as well as the magnitude of the seismic event. The site is similar to most of Southern California with respect to hazards associated with earthquakes. The hazards associated with earthquakes are primary hazards (such as ground shaking and surface rupture) and secondary hazards (such as liquefaction, seismically induced settlement, landsliding, tsunamis, and seiches).

The seismic hazard for the site and the surrounding Corona area is considered high based on the location of nearby active faults. Consequently, the site could experience strong ground shaking as a result of an earthquake originating on any of the nearby faults, discussed below. (a) Earthquake Faults
Faults in California are considered active, potentially active, and inactive based on criteria developed by the California Geological Survey (CGS) for the Alquist-Priolo Earthquake Fault Zoning Program. A fault is considered active that has had surface displacement within Holocene time (approximately the last 11,000 years). A potentially active fault is a fault that has demonstrated displacement of Quaternary age deposits (last 1.6 million years). Inactive faults have no documented movement in the last 1.6 million years.

Documented surface displacements have occurred on the Whittier-Elsinore Fault Zone in the last 11,000 years (Holocene) and the zone is, thus, mapped as an active fault based on the presence of tectonic 7 Op. Cit., page 20. 8
Op. Cit., page 21. 9
Ginter and Associates, Inc., Preliminary Geotechnical Investigation and Grading Plan, April 25, 2014, page 22.

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geomorphic features such as faceted spurs, displaced drainages and linear troughs. The Whittier-Elsinore Fault Zone splays into three major strands (see Plates I and IV of the Geotechnical Report) approximately 2,000 feet to the east of the project site. The Chino Fault, which is the easternmost strand, trends north- northwest across the Santa Ana River and along the east side of the Puente Hills, northeast of the study site.

The center strand is mapped as the Main Street Fault which is the northern continuation of the Elsinore Fault. The westernmost splay is the traditionally mapped Whittier Fault. Near Fresno Canyon, the Whittier Fault "bends" west-northwest across Santa Ana Canyon and then resumes a northwest trend along the west flank of the Puente Hills. The southernmost strand(s) of the Whittier Fault is also known as the Eagle Fault.

The project site thus lies within a tectonic wedge formed by the branching of the Whittier-Elsinore Fault Zone into three identifiable stands. 10 The relationship of the project site to these three Alquist-Priolo Fault Zones is illustrated in Figure 4.E-2, Alquist-Priolo Fault Zones in Project Area. The Main Street Fault appears to die out southeast of Wardlow Canyon, near Mabey Canyon and the northwest corner of the project site (see Plates I and IV of the Geotechnical Report). Two reasonably distinct scarps are particularly evident east of the project site near Mangular Avenue (see Plate III of the Geotechnical Report). Pleistocene alluvial fans that emanate from the high order canyons along the mountain front are beheaded by right lateral slip along the Main Street Fault, are now cut-off from their source canyons and are elevated above Temescal Canyon floor. The California Geological Survey (2003) maps the “main” branch of the Main Street Fault as trending into and terminating near the mesa in the northwest corner of Skyline Heights (similar to Plate I of the Geotechnical Report) with the corresponding Alquist-Priolo zone enclosing the entire mesa. However, the Alquist-Priolo trace of the Main Street Fault is overlain by un-faulted upper Pleistocene sediments and is, thus, not active at the project site.11 The Alquist-Priolo Zones also encompass both the Tin Mine Fault, which also encroaches onto the project site. Based on literature review, aerial photographic analyses, field mapping and logging of about 6000 lineal feet of fault trenches, the on-site part of the Tin Mine Fault is found to be overlain by un-displaced pre- Holocene deposits and is also assessed to be not active according to Alquist Priolo definition.12 The northeast-trending Eagle Fault characteristically thrusts Jurassic and Cretaceous rocks over Cretaceous and Tertiary sediments along the northeast flank of the Santa Ana Mountains (see Plate IV of the Geotechnical Report). A similar fault was mapped to the south of Tin Mine Canyon. Most fault movement occurred in Pliocene time, the earliest displacements along the Whittier-Elsinore Fault Zone, which does not place the Eagle Fault in an Alquist-Priolo fault zone. However, local and regional stratigraphic and structural relationships suggest that the Eagle Fault has contributed to slip along the Whittier-Elsinore Fault Zone.

Prior investigators (Gray, 1961; Weber, 1977; Gray et al., 2002) have either inferred or mapped several other faults on, or near, the project site. Based on the present site-specific investigation, these faults either do not exist or are pre-Holocene in age. Evidence points to bedding parallel differential erosion of sandstone and claystone beds in the Silverado Formation as the genesis of lineaments in the Silverado Formation Specifically, the absence of Silverado Formation north of Kroonen Canyon precludes the presence of such a 10 California Division of Mines and Geology (CDMG),Gray 1961; CDMG 1965;Weber, 1977, Gray et al, 2002; CDMG, 1980, cited in Ginter and Associates, Inc., Preliminary Geotechnical Investigation and Grading Plan, April 2014. 11 Ginter and Associates, Inc., Preliminary Geotechnical Investigation and Grading Plan, April 2014, page 30. 12 Op. Cit, pages 27, 28, and 33.

Regional Fault Map of Southern California FIGURE
Skyline Heights Project 4.E-1
Source: Ginter & Associates, Inc., 2014. N

Alquist-Priolo Fault Zones in the Project Area FIGURE
Skyline Heights Project 4.E-2
Source: Ginter & Associates, Inc., 2014. N
N.A.P.

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fault, and trenching exposed no significant faults. The Ladd-Silverado contact and key fossiliferous and mudstone beds within the Silverado Formation are unbroken across the mapped trace of the “Whittier Fault.

The trenching performed on 2005 and 2007 intersected many small faults and shears. These, however, occur near the axial (hinge) trace of the Kroonen syncline, have displacements less than about one to two feet, are carbonate-filled and healed, and in many places capped by unbroken late Pleistocene soils or weathered surfaces. Similar small faults and shears, as exposed in the trenches, occur in the hard, brittle conglomerate of the Ladd Formation north of Kroonen Canyon. Although trenching exposes the faults that have small displacements, no obvious lateral continuity occurs, the displacements are healed and do not displace late Pleistocene weathered surfaced. Further, they have no surface expression and many “die-out” upward and downward within the bedrock.13 Recent fault investigations in the area are illustrated in Figure 4.E-3, Project Site Relative to Recent Fault Investigations. The Cucamonga fault is located approximately 20 miles north of the site. The Cucamonga fault is part of a series of faults coincident with the southern margin of the San Gabriel Mountains known as the Transverse Ranges frontal fault system. The San Fernando fault of this system ruptured during the 1971 magnitude 6.7 San Fernando earthquake. The Sierra Madre fault, continuing west from the termination of the Cucamonga fault at San Antonio Canyon, is located 19.5 miles north-northwest of the site.

The San Bernardino segment of the San Jacinto fault zone is located approximately 25 miles northeast of the site. The San Jacinto fault zone is a system of northwest-trending faults characterized by multiple parallel strands in the northern San Bernardino Valley. These include the Lytle Creek, the Glen Helen, and the Claremont faults. More large historic earthquakes have occurred on the San Jacinto fault than any other fault in Southern California. The San Bernardino Valley segment of the San Jacinto fault may be accommodating much of the motion between the Pacific plate and the North American plate in this area. The Working Group on California Earthquake Probabilities tentatively assigned a 37 percent (+/- 17 percent) probability of a major earthquake on the San Bernardino Valley segment of the San Jacinto fault for the 30-year interval from 1994 to 2024.

The San Bernardino segment of the San Andreas fault zone is located 30 miles northeast of the site. The San Andreas fault is one of California's most prominent geological and geographic features and extends from the southeastern portion of the state northwest to the offshore area northwest of Point Arena. The San Andreas fault is characterized by youthful fault scarps, vegetational lineaments, springs, and offset drainages and has produced large historic and pre-historic earthquakes. The Working Group on California Earthquake Probabilities tentatively assigned a 28 percent (+/- 13 percent) probability to a major earthquake occurring on the San Bernardino Mountains segment of the San Andreas Fault between 1994 and 2024. (b) Landslide and Lateral Spreading
Several relatively small, surficial onsite landslides or suspected landslides have been mapped on-site. Most are concentrated in the northern part of the site on steep slopes comprised of Ladd Formation. A moderately large landslide is mapped easterly subjacent to proposed Lots 58 through 64. However, most of the mapped limits of the feature are off-site. Nonetheless, as shown on the Tentative Map, proposed development would be affected by a slide. For instance, removal of slide debris in the process of providing adequate support of 13 Op. Cit, page 30.

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the planned fill in this area could prove difficult near a property line that is within the slide limits. As noted, the offsite part of the landslide might need to be investigated in light of the current development plans.

Prior geotechnical investigation of the project site encountered 12.5 feet of landslide debris. Based on field investigation, the entire slide is seemingly a composite of relatively shallow failures associated with fractured and clay-rich Silverado Formation. Currently mapped landslides are seemingly related to the presence of steep natural slopes, colluviated swales and fractured or clay-rich rock. Seepage (i.e. springs) may also contribute to local zones of instability. The generally lithified and steeply dipping bedrock is not usually amenable to deep-seated landslides.14
(c) Subsidence
The site is located in an area identified by County of Riverside as having a potential for subsidence. However, according to the City of Corona General Plan, the area of the site exhibits no indications of significant regional subsidence. An area of documented subsidence is located in the Chino Valley, approximately 10 miles northwest of the site. Subsidence is not documented within the vicinity of the site. The potential for subsidence at the site is considered low.
(d) Liquefaction
Liquefaction is a phenomenon that predominantly occurs in saturated, cohesionless soils during relatively severe earthquake ground motions. In general, during ground motion, saturated sands tend to compact and decrease in volume and if drainage is unable to occur, an increase in pore water pressure may result. If the pore water pressure becomes equivalent to the overburden pressure, the effective stress becomes zero and consequently, the soil loses its strength and is considered to be in a liquefied state. Post-liquefaction effects at a site can manifest in several ways and may include ground deformations, loss of shear strength, lateral spread, dynamic settlement and flow failure. Liquefaction potential is greatest in loose, poorly graded sands and silty sands with mean grain size in the range of 0.1 to 0.2 millimeters. Other factors that need to be considered are groundwater, confining stresses, relative density, intensity and duration of ground shaking.

It is generally accepted that soils possessing clay content (particle size <0.005 mm.) greater than 15 to 20 percent may be considered non-liquefiable (Southern California Earthquake Center, 1999 and Blake, 1986).

Liquefaction requires relatively shallow groundwater and owing that on-site groundwater is greater than several hundred feet in depth, the likelihood of liquefaction at the site is remote. The Silverado and Ladd Formations, as well as un-weathered Pleistocene alluvium that underlie the site, are not considered susceptible to liquefaction. However, Holocene alluvium (Qal1-2), landslide debris (Qls), topsoil and undocumented fills (Af) are potentially liquefiable, if saturated. 15 Liquefaction Zones in the area and the City of Corona, are illustrated in Figure 4.E-4, Riverside County Liquefaction Zones. As shown in Figure 4.E-4, areas of “low” potential liquefaction are located in the Mabey Canyon and Kroonen Canyon areas of the site.

The remainder of the site is not identified as having any liquefaction potential. 14 Op. Cit, page 22. 15 Op. Cit., pages 35 and 36.

Project Site Rela ve to Recent Fault Inves ga ons FIGURE Skyline Heights Project 4.E-3
Source: Ginter & Associates, Inc., 2014. N
N.A.P.

Riverside County Liquefac on Zones FIGURE
Skyline Heights Project 4.E-4
Source: Ginter & Associates, Inc., 2013. N

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(e) Dry Sand Settlement
Dry sand settlement is a result of earthquake-induced stresses creating strains within partially saturated soils. These strains cause a rearrangement of the soil structure, decreasing the void ratio of the soil, and ultimately creating settlement. The soils that typically are susceptible to dry sand settlement are loose, poorly graded sands and silty sands with mean grain size in the range of 0.1 to 0.2 mm. Generally, soils possessing clay content (particle size <0.005mm) greater than fifteen (15) to twenty (20) percent are typically not susceptible to dry sand settlement (Martin and Lew, 1999). Other factors that must be considered are confining stresses, relative density, intensity and duration of ground shaking, previous stress history and the age of the deposits. Based on a review of the data from prior subsurface investigation, the potential is considered remote, provided the proposed design and remedial grading are accomplished as outlined herein.
(5) Soils
(a) Expansive Soils
Based on the laboratory tests performed during site investigation, it is anticipated that the majority of onsite soils would classify as "very low" to "medium" in expansion potential according to Table 18-I-B of the 1997 UBC. However, portions of the Silverado Formation could produce materials ranging from very high to critical in expansion potential.
(b) Compressible Soils
Unconsolidated sediments occupying active channels in the major canyons and low order swales are shown as Holocene alluvium (Q1-2 on the various geologic maps in the Geotechnical Report). These deposits vary in thickness from a few feet to more than 20 feet and are generally of low density and considered to be compressible. In addition, unmapped prisms of compressible soils likely lie at the base of onsite slopes, or occupy swales on those slopes. These accumulations stem from weathering, dislodgement and downslope transport (by either water or creep) of debris derived from local bedrock. Although colluvium (loose, unconsolidated sediment) was encountered in a few of exploratory trenches, the steep nature of most of the slopes and heavy vegetative growth prevented exploration of these soils. Colluvium is estimated to range from approximately five to 15 feet in depth.16 Non-engineered fill exists at the Kroonen Clay Prospect near the center of the project site. It is anticipated that artificial fill in this region locally reaches a depth ranging from five to 20 feet. Fault trenches created during the 2005 on-site geologic investigation are located primarily in areas of planned cut and were backfilled with non-engineered fill.17
16 Op. Cit., page 21. 17 Op. Cit., page 22.

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b. Regulatory Framework
(1) Federal
(a) Earthquake Hazards Reduction Act
1997 U.S. Code, Title 42 – The Public Health and Welfare, Chapter 86 – Earthquake Hazards Reduction, §§ 7704 – National Earthquake Hazards Reduction Program, (Earthquake Hazards Reduction Act), was enacted in 1997 to “reduce the risks to life and property from future earthquakes in the United States through the establishment and maintenance of an effective earthquake hazards and reduction program.” To accomplish this, the Act established the National Earthquake Hazards Reduction Program (NEHRP). The program was significantly amended in November 1990 by NEHRP, which refined the description of agency responsibilities, program goals, and objectives. NEHRP’s mission includes improved understanding, characterization, and prediction of hazards and vulnerabilities; improvement of building codes and land use practices; risk reduction through post-earthquake investigation and education; development and improvement of design and construction techniques; improvement of mitigation capacity; and accelerated application of research results. The NEHRP designates the Federal Emergency Management Agency (FEMA) as the lead agency of the program and assigns it several planning, reports, and coordinating responsibilities.

Programs under NEHRP inform and guide planning and building code requirements such as emergency evacuation responsibilities and seismic code standards such as those to which the Project would be required to adhere.
(b) Federal Soil Protection Act
The purpose of the Federal Soil Protection Act, published within the Federal Law Gazette on March 17, 1998, is to protect or restore the functions of the soil on a permanent sustainable basis. Protection and restoration activities include prevention of harmful soil changes, rehabilitation of the soil of contaminated sites and of water contaminated by such sites, and precautions against negative soil impacts. If impacts are made on the soil, disruptions of its natural functions and of its function as an archive of natural and cultural history would be avoided, as far as practicable. In addition, the requirements of the Federal Water Pollution Control Act, also referred to as the Clean Water Act (CWA) through the National Pollution Discharge Elimination System (NPDES) permit provide guidance for protection of geologic and soil resources. (2) State
(a) Alquist-Priolo Earthquake Fault Zoning Act
The Alquist-Priolo Earthquake Fault Zoning Act (Pub. Resources Code, §§ 2621-2624) was enacted in 1972 to address the hazard of surface faulting to structures for human occupancy.18 The primary purpose of the Alquist-Priolo Earthquake Fault Zoning Act is to prevent the construction of buildings intended for human occupancy on the surface traces of active faults. The Alquist-Priolo Earthquake Fault Zoning Act requires the State Geologist to establish regulatory zones, known as “earthquake fault zones”, around the surface traces of active faults and to issue maps to assist cities and counties in planning, zoning, and building regulation functions. Local agencies must enforce the Alquist-Priolo Earthquake Fault Zoning Act in the development permit process, where applicable, and may be more restrictive than State law requires. The Act requires that, prior to approval of a project, a geologic study be conducted to define and delineate any hazards from 18 The Act was originally entitled the Alquist-Priolo Geologic Hazards Zone Act.

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surface rupture. A geologist registered by the State of California, within the lead agency’s organization or retained by the lead agency for the project, must prepare this geologic report. A 50-foot building setback from any known trace of an active fault is required. The Alquist-Priolo Earthquake Fault Zoning Act and its regulations are presented in California Department of Conservation, California Geological Survey, Special Publications (SP) 42, Fault-rupture Hazard Zones in California. (b) Seismic Hazards Mapping Act
The Seismic Hazards Mapping Act of 1990 (Pub. Resources Code, §§ 2690-2699) addresses the effects of strong ground shaking, liquefaction, landslides, and other ground failures due to seismic events. Under the Seismic Hazards Mapping Act, the State Geologist is required to delineate “seismic hazard zones.” The State Mining and Geology Board provides additional regulations and policies to assist municipalities in preparing the Safety Element of their General Plan and encourage land use management policies and regulations to reduce and mitigate those hazards to protect public health and safety. Under Public Resources Code section 2697, cities and counties shall require, prior to the approval of a project located in a seismic hazard zone, a Geotechnical Report defining and delineating any seismic hazard.

State publications supporting the requirements of the Seismic Hazards Mapping Act include the California Geological Survey SP 117, Guidelines for Evaluating and Mitigating Seismic Hazards in California, and SP 118, Recommended Criteria for Delineating Seismic Hazard Zones in California. The objectives of SP 117 are to assist in the evaluation and mitigation of earthquake-related hazards for projects within designated zones of required investigations and to promote uniform and effective statewide implementation of the evaluation and mitigation elements of the Seismic Hazards Mapping Act. SP 118 implements the requirements of the Seismic Hazards Mapping Act in the production of Probabilistic Seismic Hazard Maps for the State. (3) Local
The California Government Code section 65300 requires general plans to include “a safety element for the protection of the community from any unreasonable risks associated with the effects of seismically induced surface rupture, ground shaking, ground failure, tsunami, seiche, and dam failure; slope instability leading to mudslides and landslides, subsidence and other geologic hazards known to the legislative body; flooding; and wildland and urban fires.” As such, the City’s Public Health and Safety Element (Chapter 6 of the General Plan) addresses hazards which must be considered in the physical development of the City, including seismic, geologic and erosion. An analysis of project consistency with the City’s Public Health and Safety Element regarding geology and soils issues is provided in the Analysis of Project Impacts subsection, below (see Threshold 6).

With regard to soils, the Infrastructure and Public Services Element contains goals and policies regarding the assessment of stormwater runoff and the implementation of Best Management Practices (BMPs) during construction. All development projects with the City must comply with CBC Chapter 70 standards, which ensure implementation of appropriate measures during grading activities to reduce soil erosion. Title 15 of the City of Corona Municipal Code requires that all development projects to obtain a grading permit. All work requiring a grading permit is required to have an approved Erosion Control Plan. Please also see Section 4.H, Hydrology and Water Quality, of this Draft EIR for a detailed discussion regarding groundwater and stormwater runoff.

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2. ENVIRONMENTAL IMPACTS
a. Methodology
The technical analyses supporting the impact conclusions in the following section are based on the analysis contained in the Preliminary Geotechnical Investigation and Grading Plan prepared by Ginter and Associates, Inc., on April 25, 2014. The conclusions in the report were primarily derived from the following tasks:

Review of available geologic and geotechnical literature, reports, maps and agency information; Review of prior subsurface exploration consisting of trenching and borings; Collection of relatively undisturbed and bulk samples at selected depth intervals from the soil borings and transportation of the samples to a laboratory for testing; Laboratory testing of selected samples to evaluate engineering characteristics of the onsite earth materials within the exploration depths;
Geotechnical evaluation of collected test boring and relevant engineering analyses; and Geologic field reconnaissance mapping to verify the aerial distribution of earth units and significance of surficial features as compiled from documents, literature and reports reviewed; and Recommendations for foundation design, grading and earthwork, and pavement.

Please refer to Preliminary Geotechnical Investigation and Grading Plan, contained in Appendix F of this Draft EIR, for a detailed discussion of the subsurface exploration, soil sampling, and laboratory tests and procedures. Data and conclusions from the analyses in the report were used to determine potential impacts from the project related to site geology and soils parameters. These impacts were compared against the Thresholds of Significance set forth below to determine the level of significance of potential impacts. A detailed seismic hazard evaluation of the CBC Seismic Design Parameters and Peak Ground Acceleration Data was determined utilizing USGS Earthquake Ground Motion Parameters Version 5.1.0 (Revised 2/10/2011) (see the Geotechnical Report included as Appendix F of this Draft EIR). The geotechnical study also evaluated the hazards associated with earthquakes that include primary hazards such as ground- shaking and surface rupture, as well as secondary seismic hazards such as liquefaction, seismic settlement and earthquake induced landsliding.
b. Thresholds of Significance
Appendix G of the CEQA Guidelines (the Initial Study Environmental Checklist form) and the City’s Initial Study Checklist include questions relating to geology and soils that are utilized as the thresholds of significance in this section (Thresholds 1-6). Accordingly, the proposed project may create a significant environmental impact if it would:

Threshold 1: Expose people or structures to potential substantial adverse effects, including the risk of loss, injury or death involving:

Rupture of a known earthquake fault, as delineated on the most recent Alquist-Priolo Earthquake Fault Zoning Map issued by the State Geologist for the area or based on other

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substantial evidence of a known fault (Refer to Division of Mines and Geology Special Publication 42);
Strong seismic ground shaking;
Seismic-related ground failure, including liquefaction; or Landslides.

Threshold 2: Result in substantial soil erosion or the loss of topsoil.

Threshold 3: Be located on a geologic unit or soil that is unstable, or that would become unstable as a result of the project, and potentially result in on- or off-site landslide, lateral spreading, subsidence, liquefaction or collapse.

Threshold 4: Be located on expansive soil, as defined in Table 18 1 B of the Uniform Building Code (1994), creating substantial risks to life or property.

Threshold 5: Have soils incapable of adequately supporting the use of septic tanks or alternative waste water disposal systems where sewers are not available for the disposal of waste water.

Threshold 6: Conflict with an applicable plan, policy or regulation adopted for the purposes of avoiding or mitigating physical impacts associated with geology and soils. c. Project Design Features
There are no specific Project Design Features (PDFs) that relate to geology and soils impacts. However, the proposed project would comply with all applicable building requirements related to geology and soil conditions. Recommendations from the Geotechnical Report would be incorporated into the project, as required by Mitigation Measure GEO-1 below. Also, with regard to impacts pertaining to soil erosion or the loss of topsoil, the project would implement numerous BMPs as detailed in the Water Quality Management Plan (WQMP) for the project. The analysis below refers to Section 4.H, Hydrology and Water Quality, of this Draft EIR for a description of the BMPs proposed for the project. d. Analysis of Project Impacts
(1) Earthquake Fault Rupture, Ground Shaking, Ground Failure, and Landslides Threshold 1: Expose people or structures to potential substantial adverse effects, including the risk of loss, injury or death involving:

Rupture of a known earthquake fault, as delineated on the most recent Alquist-Priolo Earthquake Fault Zoning Map issued by the State Geologist for the area or based on other substantial evidence of a known fault? Refer to Division of Mines and Geology Special Publication 42.

Strong seismic ground shaking?
Seismic-related ground failure, including liquefaction? Landslides?

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Impact 4.E-1 Project implementation could expose people or structures to strong seismic ground shaking, seismic-related ground failure, landslides and other ground failure hazards. However, adherence to the design and remedial grading recommendations of the Geotechnical Report, as required by Mitigation Measures GEO-1 through GEO-23, as well as compliance with applicable regulatory requirements would reduce such impacts to a less than significant level.

Prior site-specific fault investigations of the Main Street, Tin Mine and associated faults concluded that active faults do not exist in proposed development areas. However, the age of last movement along a fault exposed in Trench T-12, in the northwest corner of the site is presently unknown owing to lack of dateable overlying sediments.19 As such, a provisional habitable structures setback zone for the fault until has been conservatively recommended until additional investigation may be undertaken. However, the Geotechnical Report considers this a conservative interpretation because the fault has no surface expression and its length is limited based on the un-faulted strata observed in the north-central part of the project site south of Mabey Canyon. Furthermore, prior investigators also concluded that the Alquist-Priolo trace of the Main Street Fault is clearly overlain by un-faulted upper Pleistocene sediments near Mabey Canyon and is, therefore, not active in the northwest part of the site south of Mabey Canyon, which precludes the need for habitable structures setbacks in that area.20 Nonetheless, in order to address uncertainties regarding the Main Street Fault, a minimum habitable structures setback of 50 feet on each side of the fault trace would be applied to Lots 230 through 234 of the project’s Tentative Tract Map until additional fault investigations can be undertaken to determine the activity of the fault. Refer to Figure 4.E-5, Fault Setback Zone, for an illustration of the fault setback zone and potentially affected residential lots. However, upon completion of the prescribed additional investigation, lots that are not capable of meeting recommended habitable structure setback would be deemed as non-buildable. With adherence to the design and remedial grading specific recommendations of the Geotechnical Report, as required by Mitigation Measures GEO-1 through GEO-23, the potential for fault rupture affecting any on-site development would be less than significant.

The Geotechnical Report states, however, that the potential for strong, seismically-induced ground motion is substantial due to the proximity of major active faults. According to the Geotechnical Report, horizontal ground motion representing 10 percent probability of exceedance in 50 years (475-year return period) is anticipated to be 0.6436.21 Design parameters for this potential level of groundshaking are provided in Appendix III of the Geotechnical Report. Because of steep natural slopes and, very locally, adverse bedding angles, the potential for earthquake-induced landslides exists. However, as discussed in the Geotechnical Report, with completion of remedial grading recommended in the report, as required by Mitigation Measures GEO-1 and GEO-2 below, seismically induced landslides are not anticipated to adversely impact proposed development.22As further discussed in the Geotechnical Report, earthquake-induced stresses may result in dry sand settlement within partially saturated soils. These strains cause a rearrangement of the soil structure, decreasing the void ratio of the soil, and ultimately creating settlement. The soils that typically are susceptible to dry sand settlement are loose, poorly graded sands and silty sands with average grain size 19 Pacific Soils Engineering, Inc. (2004 and 2005) cited in Ginter & Associates, April 25, 2014, page 36. 20 Pacific Soils Engineering, Inc. (2005) cited in Ginter & Associates, April 25, 2014, page 36. 21 Ginter & Associates, Inc., April 25, 2014, page 34, United States Geological Survey (USGS) Seismic Design Parameters. 22 Ginter & Associates, April 25, 2014, page 36.

Fault Setback Zone FIGURE
Skyline Heights Project 4.E-5
Source: KWC Engineers, 2015. N
0 120 Feet

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ranging from 0.1 to 0.2 mm. Soils possessing clay content (particle size <0.005mm) greater than fifteen to twenty percent are typically not susceptible to dry sand settlement.23 Other factors include confining stresses, relative density, intensity and duration of ground shaking, previous stress history and the age of the deposits. However, based on a review of soils data from prior subsurface investigations, the potential for dry sand settlement is considered remote, provided the proposed design and remedial grading are accomplished as outlined in the Geotechnical Report, as required by Mitigation Measures GEO-1 through GEO-15.24 With regard to liquefaction, limited portions of the site, including the Mabey Canyon and Kroonen Canyon areas, are located in “low” or “very low” liquefaction zones. Other areas of the site are not identified as having any liquefaction potential. According to the Geotechnical Report, perched groundwater was encountered during prior geological investigations at 39 feet below ground surface. No groundwater was encountered during the more recent fault investigations. The geotechnical also cited a prior report, which estimated the regional groundwater surface to be 100 to 200 feet below the existing ground surface.25 In addition, the Silverado and Ladd Formations, as well as unweathered Pleistocene alluvium underlying the site, are not considered susceptible to liquefaction. However, on-site Holocene alluvium (Qal1-2), landslide debris (Qls), topsoil and undocumented fills (Af) are potentially liquefiable, if saturated. According to the Geotechnical Report, the recommended removal and replacement of those materials within the proposed development with drained, engineered fills, as required by Mitigation Measures GEO-5 and GEO-6, would reduce the susceptibility to liquefaction to a minimal level upon completion of grading.26 Based on these conditions, the potential for soil liquefaction and/or seismic settlement is considered to be very low.

Although groundwater was not encountered during prior subsurface investigation within the alluvium onsite, access was limited and certain alluvial areas within Krooner Canyon could not be investigated. If "saturated" alluvium is encountered that possesses a degree of saturation of 85 percent of more and is consistent with depth to bedrock, an additional liquefaction investigation may be required and dynamic settlement recommendations for those areas would likely change.

The project would be designed, engineered, and constructed to meet all applicable local and state seismic safety requirements and would incorporate recommendations contained in the Geotechnical Report, as required by Mitigation Measures GEO-1 through GEO-23 below. Furthermore, the City would have review and approval authority over grading and building plans to ensure compliance with all applicable standards.

Given compliance with applicable requirements and recommendations of the Geotechnical Report, the project would not result in significant impacts with regard to seismic or seismic-related hazards. (2) Soil Erosion
Threshold 2: Result in substantial soil erosion or the loss of topsoil? Impact 4.E-2 Project construction would require mass grading on the site and removal of fill, alluvium, and other loose materials. Best Management Practices would be implemented in accordance with an approved Erosion Control Plan. After construction, any non-paved, exposed areas would be 23 Martin and Lew (1999) cited in Ginter & Associates, Inc., April 25, 2014, page 35. 24 Ginter & Associates, Inc., April 25, 2014 , pages 35-36. 25 Weber (1977) cited in Ginter &Associates, Inc., April 25, 2014, page 22. 26 Ginter & Associates, Inc., page 35.

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landscaped. Therefore, with compliance with applicable requirements, impacts regarding soil erosion or the loss of topsoil would be less than significant.

The project would require mass grading and the removal of undocumented fill, alluvium, colluvium, and landslide debris at the site. Construction activities would be required to comply with CBC Chapter 70 standards, which would ensure implementation of appropriate measures during grading activities to reduce soil erosion. In addition, the project would be subject to regional and local regulations pertaining to construction activities. More specifically, since the project would disturb more than one acre of land, the project would be required to comply with the provisions of the General Construction Activity Stormwater Permit adopted by the State Water Resources Control Board (SWRCB), which would require the incorporation of Best Management Practices (BMPs) to limit the extent of eroded materials from the construction site. Furthermore, the project would comply with Title 15 of the City of Corona Municipal Code, which requires that an Erosion Control Plan be approved prior to issuance of a grading permit.

After construction, exposed areas would be landscaped. The installation of landscaping would serve to protect the soil and reduce any erosion that could occur. Therefore, with compliance with applicable regulations during construction and operation, impacts regarding soil erosion or the loss of topsoil would be less than significant.
(3) Ground Failure
Threshold 3: Be located on a geologic unit or soil that is unstable, or that would become unstable as a result of the project, and potentially result in on- or off-site landslide, lateral spreading, subsidence, liquefaction or collapse?
Impact 4.E-3 Mass grading at the site has the potential to reduce slope stability and result in settling and other geologic hazards. However, adherence to the design and remedial grading and monitoring recommendations of the Geotechnical Report, as required by Mitigation Measures GEO-1 through GEO-15, would reduce such impacts to a less than significant level.

The project proposes cuts and fills to maximum design depths of approximately 130 feet (vicinity of Lot 123), excluding utility excavation, and 138 feet (vicinity of Lot 223), respectively. Cut slopes would range from small, two-foot-high side yard split slopes to 140 feet at 2:1 slope ratios. One 1.5:1 cut slope approximately 80 feet high is proposed. Fill slopes would range from small, less than two-foot-high side yard split slopes to 160 feet at 2:1 slope ratios. The majority of cut and fill slopes are designed at a slope ratio of 2:1. The Engineering Geologist would observe cut slopes and cut slope stabilization backcuts during grading.

Cut slopes within the Williams and Ladd Formations may expose adverse bedding that would require remediation. The cut slope superjacent to Lots 278 and 279 is anticipated to require replacement with a buttress fill and probable buttresses are anticipated for the cut slope above Lots 261 through 267 and below Lots 247 through 255. Within the Ladd Formation, the majority of the cut slopes would expose bedding dipping into the slope or at an angle steeper than the proposed cut slopes (greater than 60 degrees). Cut slopes within the Ladd and Silverado Formations that expose bedding dipping into the slope or at an angle steeper than the proposed cut slopes are expected to be grossly stable; however, the final determination would be made based on exposed conditions during grading.

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Cut slopes within the Ladd and Silverado Formations may also expose conglomerate resulting in poorly cemented sands, cobbles and boulders at finish grade, producing a rough uneven surface. These cut slopes would be evaluated in the field by the Project Engineering Geologist or Geotechnical Engineer. Replacement of those slopes with compacted stabilization fills may be required. Cut slopes exposing alluvial/colluvial soils (Qal) would require replacement with a drained stabilization fill. Typically, such corrective grading would be constructed with a minimum key width corresponding to one-half the full height of the superjacent slope, but not less than 15 feet. Minimum key depths at the toe would be two feet. All stabilization fills would be provided with a backdrain and outlet system as detailed in the Geotechnical Report.

The highest fill slope would be approximately 160 feet in height and located subjacent to Lot 68. Based on the slope stability analyses, the 2:1 fill slopes 160 feet and less in height, when properly constructed with onsite materials, are expected to be grossly stable. Keys would be constructed at the toe of all fill slopes where unsuitable soil removals do not accomplish a minimum key width of one-half the slope height plus bench widths or 20 feet, whichever is greater. Minimum key depths at the toe would be two feet. Due to grading limit restrictions, removals of unsuitable soils beyond the proposed toe may be limited; therefore, additional slope maintenance would be expected in the areas where a 1:1 projection into approved materials cannot be achieved.27 Where a transition of cut and fill occurs across a finished lot, it will be necessary to overexcavate the bedrock portions and replace it with compacted fill. The depth of bedrock overexcavation would be equal to one-third the maximum fill depth (after removals) on the fill side of the transition. The Geotechnical Report recommends that cut pads be overexcavated a minimum of five feet to provide a uniform foundation material, which is required by Mitigation Measure GEO-4. Difficult excavation with a backhoe can be expected in some street areas.

Because the project would involve deep fills in the canyon areas and side-hill fill slopes, the fill would be compacted to the minimum relative compaction recommended in the Geotechnical Report, as required by Mitigation Measure GEO-6. This would reduce the amount of fill settlement to a less than significant level.

Fill materials would be spread in thin lifts, moisture conditioned to about one to two percentage points over optimum moisture content and compacted to a minimum of 90 (or 93) percent of the laboratory maximum dry density as determined in accordance with ASTM Test Method D-1557. Each lift would be treated in a like manner until the desired finished grades are achieved. Fill slopes would also be constructed at the minimum relative compactions, with the exception of the outer three feet of the slope face, which can be placed at 90 percent relative compaction.

Because the maximum depth of proposed canyon fill is approximately 138 vertical feet, the areal loading from fill placement would cause settlement due to the compressibility of the fill materials. The magnitude of settlements would depend on the thickness of fill and the compressibility characteristics of fill materials.

Considering the maximum fill depth and anticipated consolidation characteristics of the fill materials, the compacted fill may approximately six to eight-inches. Due to the granular nature of the site soils, the majority of this settlement would occur during grading operations and long-term secondary settlement would be negligible. The Geotechnical Report proposes positioning settlement monuments at strategic locations in the deeper fill areas and recommends periodic surveys by the Project Civil Engineer to evaluate the magnitude and progress of settlements. These would be monitored by the Project Civil Engineer on a 27 Ginter & Associates, Inc., April 25, 2014, page 46.