Agenda packet — Brea City Council, June 2, 2026 (part 12 of 19)

environment, and to again reiterate policy suggestions for inclusion in the GPU that can reduce potential environmental impacts.

I. Introduction and Background
As proposed, the Brea GPU and BCSP (“Project”) would allow significant amounts of new development in Brea:

Residential
Units
Population Non-Residential Square
Footage (NRSF)
Jobs
Existing Conditions (2025) 16,345 46,585 21,480,414 51,937 Proposed GPU and BCSP
(2050 horizon)
23,736 67,647 30,587,193 73,709
Increase
(Subject of EIR analysis)
7,391 units
(31% increase)
21,062 persons
(31% increase)
9,106,779 square feet
(30% increase)
21,772 jobs
(30% increase)
This table demonstrates notable changes in the amount of:
• Potential for additional Residential Units and Population in the Hillside Residential, MU-50, Brea 265 Specific Plan, and Proposed Brea Core Study Area GP land use designations; and
• Potential for additional Non-Residential Square Footage and Jobs in the General Commercial, General Industrial, Light Industrial, MU-18, MU-50, Public Facilities, Recreational Commercial, Brea 265 Specific Plan, Brea Industrial Specific Plan, and Proposed Brea Core Study Area GP land use designations.

Increases of roughly 30% in each of the categories above table show the substantial change in the number of people, buildings, and jobs for the City. When examining the environmental impacts of this growth at the programmatic level, the City must disclose all it reasonably can now. The PEIR acknowledges the “EIR can serve to streamline environmental review of future projects.” PEIR at 1-1. In fact, under recentlyadopted State legislation including Assembly Bill 130 (2024), many projects that conform with the General Plan land use designations and associated zoning will be exempt from further CEQA review. Thus, the GPU PEIR analysis may be the first, and last, consideration of environmental impacts from those exempt categories of projects.

For this reason, it is imperative that the PEIR thoroughly and properly analyze and, if necessary, mitigate for, the potential environmental impacts of the development allowed City of Brea
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under the GPU and BCSP. See Cleveland National Forest Foundation v. San Diego Assn. of Governments (2017) 17 Cal.App.5th 413, 441 (program EIRs must provide sufficient detail to decisionmakers so that they can evaluate a project’s environmental impacts). For this reason, the GPU should include policies and implementation actions that can serve to reduce the environmental impacts of future development through measures that be taken either proactively or in coordination with future projects. CEQA Guidelines § 15126.4(a)(2).

II. General Plan Policy Considerations
The City of Brea has long supported smart development within the City while valuing the recreation, open space, and wildlife habitat conservation areas that lie both within and beyond the City limits. This GPU is the perfect time to acknowledge the City’s past efforts in this area and ensure that the next 20 years are guided by the City’s Community Vision Plan published in 2024, which anticipates that “[b]alanced growth and inclusivity are valued. The natural environment, including open spaces, hillsides and wildlife, is well-preserved. The City also provides essential infrastructure and amenities to meet the needs of current and future community members. Diverse representation in decision-making fosters community cohesion. The City preserves what makes it special, while adapting to a changing world and cultivating a prosperous future for all people who live, work, and visit Brea.” See Community Vision Plan at 1.

Two key Guiding Principles from the Vision Plan are Guiding Principle 5:

Resilience for Future Generations and Guiding Principle 6: Connection to Nature.

Guiding Principle 5 explains how Brea sees itself as a forward-thinking city ready to take on the challenges of a changing climate. This principle states that “[p]roactive measures to combat extreme weather, including shade tree planting, water management practices, and wildfire preparedness, enhance both environmental sustainability and quality of life.

Through these comprehensive efforts, Brea is a resilient, livable community for current and future generations.” See Community Vision Plan at 6. Guiding Principle 6 supports Brea’s commitment to providing recreation and open spaces for human and non-humans alike. This principle recognizes that “[T]he surrounding hills and open spaces further enrich Brea’s outdoor offerings, providing opportunities for sports, leisure, and a deeper connection to nature.” See Community Vision Plan at 7.

This GPU is Brea’s opportunity to adopt policies that align with these Guiding Principles and the City’s long-standing conservation values of protecting the hills. The City has repeatedly demonstrated these values through the its support of the Wildlife Corridor Conservation Authority (WCCA), establishment of Chino Hills State Park, and formation of the Hillside Open Space Education Coalition (HOSEC). Brea’s efforts, in combination with those of other local and regional agencies, have resulted in the City of Brea
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preservation of significant areas of land in the Puente-Chino Hills corridor. In this GPU, Brea can implement policies and programs that will further the community vision as well as bolster the substantial public investments already made in open space and habitat preservation.

In our NOP comment letter, Hills For Everyone encouraged Brea to adopt GPU policies in four key categories: 1) Discouraging development in hillside areas within the Brea’s Sphere of Influence; 2) Emphasizing both fire safety and wildlife protection at the urban edge that is based on sound science and does not remove more protective habitat cover than is necessary; 3) Bringing the General Plan into compliance with new State laws that prioritize wildlife corridors and habitat connectivity; and 4) Supporting urban greening and climate resiliency. The GPU has established some laudable goals and policies, but its implementing actions fall short of identifying how the aspirational policy statements will become reality. We have identified proposed additional actions or revisions to proposed actions for several General Plan Elements that can better implement the categories listed above. All new language proposed is shown in underline.

A. Policy Direction in the Community Development (CD) Element and Urban Design Framework (Appendix A).

The Community Development Element contains goals, policies, and actions related to hillside development, infrastructure, and growth management, among others.

Hills for Everyone’s primary concern is protecting the area’s diverse hillside areas from development so they may continue to provide habitat and connectivity for the natural flora and fauna in the area. The General Plan recognizes this as an important goal and further notes that “[P]roperties designated Hillside Residential are moderately to severely constrained by unique or significant features such as ridgelines, earthquake faults, steep and/or unstable slopes, creeks, sensitive habitat, sensitive wildlife species, mapped landslides, soil conditions, accessibility issues, and wildland fire hazards. Such properties are subject to the City’s Hillside Zoning Ordinance.” GPU at 40. The GPU further acknowledges that development in these constrained areas is subject to hillside development policies and the City’s goals to preserve ridgelines, riparian areas, creeks, streams, wetlands, and wildlife habitat; avoid oil production hazards (ongoing and residual); avoid earthquake fault zones; minimize fire hazards; require adequate levels of public services; and meet project-related and cumulative infrastructure demands. Id. at

46. Although the Hillside Residential areas are physically constrained, the GPU still allows for the development of 1,663 units in the 3,325 acres with this land use designation. GPU Table CD-2 at 45. The GPU relies entirely on regulating development once it arrives, but the GPU should also contemplate making preservation an City of Brea
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economically rational choice for property owners. A Transfer of Development Rights (TDR) program would allow owners to convert hillside density rights into a tradeable asset that could be provided to infill developers who want more density in the City’s core areas. A proposed new action is included in the section below.

Existing CD Goals
CD-2: Create a visually appealing and cohesive community that emphasizes high-quality design, celebrates Brea’s distinct character, and fosters a strong sense of place through well-designed spaces, architecture, and streetscapes.

CD-4: Minimize the extent of development in the hillsides and mitigate any adverse consequences associated with urbanization.

CD-6: Promote balanced growth with supporting public services infrastructure.

Existing CD Policies
CD-2.3: Streetscape Design. Provide public space streetscapes that balance aesthetics and functionality, with a focus on the City’s arterial highways, entry gateways, and the Core Area. This includes cohesive design elements such as street furniture, lighting, drought-tolerant landscaping in medians and parkways, and monument signage that enhance Brea’s image and provide a welcoming, visually elevated experience for both residents and visitors.

CD-4.2: Constraints. Base allowable development on the ability of infrastructure, landform, physical constraints, and emergency response capabilities to support new development.

CD-4.3: Natural Grading. Encourage natural grading techniques that blend with existing topography; grading should use rounded contours on slopes to minimize disturbance. Encourage the preservation of the physical shape of the hillsides and views where feasible.

CD-4.4: Hillside Zoning Ordinance. Enforce the City’s Hillside Zoning Ordinance, which establishes standards for permitted density on slopes, subdivision design, ridgeline preservation, grading, retaining walls, and other requirements.

CD-4.5: Regional Coordination. Coordinate with Orange County and emphasize the City’s need to participate in the development review process of projects proposed in surrounding unincorporated areas. Work to ensure that such developments proceed consistent with City standards.

CD-4.6: Natural Fire Breaks. Preserve natural fire breaks through designated Open Space land use.

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CD-6.5: Growth Pattern. Strongly encourage new development in infill locations in a balanced and efficient pattern that reduces sprawl, preserves open space, and creates convenient connections to other land uses and transportation facilities.

Existing CD Actions
CD-4a: Require a constraints analysis for properties zoned Hillside Residential. The constraints analysis shall include a detailed description and mapping of slopes, geologic factors, areas prone to flooding and any sensitive biological resources.

CD-4b : Require continued implementation of the City’s Hillside Zoning Ordinance.

In addition to the goals, policies, and actions in the Community Development Element, the Urban Design Framework (General Plan Appendix A) contains a section of urban design guidelines that pertain specifically to the Hillside Residential “development type.” The General Plan specifically notes that these are recommendations:
• Preserve riparian areas, creeks, streams, wetlands, and wildlife habitat; preserve natural slopes; avoid oil production hazards (ongoing and residual); avoid earthquake fault zones; and minimize fire hazards.
• Revegetate with native and/or naturalized species where grading or other activities have disturbed the site.
• Tree selections and plantings shall utilize non-invasive species and those not prone to high flammability. In general, planting should be drought resistant and control erosion.
• Design unobtrusive dwellings, requiring stepped, single story, and low profile building and roof forms that conform to the hillside topography. Tall building forms that block views and detract from the largely undeveloped character of the hillsides are strongly discouraged.
• Incorporate architectural features that reduce bulk, such as eaves, bay windows, and varied elevations. Naturalistic materials and colors are encouraged. • Restrict construction on environmentally sensitive and visually prominent locations. Dwellings should be sited well below the ridgeline and avoid prominent landforms, site features, drainageways, and vegetation. • Use naturalistic grading techniques that blend grading with the existing topography. Grading should use rounded contours and slopes to minimize the apparent disturbance to the site.

While following these recommendations will help minimize the visual and physical impact of Hillside Residential development, most of the recommendations are City of Brea
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subjective and unenforceable in the context of State Housing law. Developing standards that are written clearly and objectively so that they can be relied upon for determining project consistency (or need for design changes to ensure consistency) is important to make these recommendations effective so that they can guide any future development in the Hillsides.

Proposed Additional Actions:

Establish objective design criteria for development in the Hillside Residential General Plan land use designation and the Hillside Residential Zoning District. The objective criteria should be derived from the recommendations in the Hillside Residential section of the Urban Design Framework.

Define thresholds for permitting development on parcels in Brea’s Sphere of Influence (SOI) that are designated Hillside Residential. Thresholds should include allowing development only when accompanied by a Fire Protection Plan and fuel modification plans, establishing minimum evacuation standards and multiple ingress/egress route requirements, and minimizing impacts to biological resources.

Establish a mapped Conservation Priority Overlay for hillside SOI parcels that meet defined ecological, geologic, or scenic threshold criteria (e.g., average slope >25%, presence of sensitive habitat, location within a mapped wildlife corridor, etc.). Within this overlay, the City shall: (a) make open space preservation the preferred outcome of any annexation discussion; and (b) require an Open Space Deed Restriction or Conservation Easement as a condition of any annexation.

Establish a Transfer of Development Rights (TDR) program that allows development potential to be transferred from high-value conservation lands in the hillsides to appropriate infill receiving zones in the city core (such as the Brea Core Specific Plan Area).

B. Policy Direction in the Community Resources (CR) Element.

The Community Resources Element acknowledges that “woodlands, grasslands, and chaparral areas provide important open space, natural resources, and scenic vistas, but also create fire hazards when development is located in or adjacent to these areas,” explicitly recognizing the tension between fire safety and habitat protection. The Brea Fire Department has set a minimum distance of 170 feet beyond the construction boundary of any property on which a new structure can be built as its fuel modification zone within the designated High Fire Hazard and Very High Fire Hazard Severity Zones.

However, one of concerns is that the 170-foot fuel modification standard is applied as a blanket rule without biological review. Current science (including work from UC City of Brea
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Cooperative Extension and CAL FIRE) supports a risk-based, site-specific approach to fuel modification that can achieve equivalent fire safety with substantially smaller disturbance in certain habitat types. As currently written, there is no distinction between habitat types in the fuel modification zones. The fuel modification requirements should have different standards for thinning in chaparral (which has evolved with fire) than clearing coastal sage scrub (which hosts California gnatcatcher and other listed species) and should be retained to the greatest degree possible. There is also no science-based fireresistant landscaping palette that is required. Fuel Modification Zone B (50 feet, replanting/irrigated) could be replanted with native, fire-resistant species that provide some habitat value, but the fuel modification standards do not require this. The June 2014 Brea fire example in the Safety Element (GPU at 170) demonstrates this is effective, but it is not codified as a standard. These items are suggested new actions to be included in the GPU.

As drafted, the GPU does not appear to comply with Assembly Bill (AB) 1889, which requires adoption of a wildlife connectivity element, or to ensure that wildlife connectivity goals, policies, and actions are included in other elements. To comply with AB 1889, the GPU must, among other things, identify and analyze connectivity areas, permeability, and natural landscape areas, identify and analyze existing or planned wildlife passage features, and consider the impacts of development and the barriers caused by development to wildlife, as defined, and habitat connectivity. Developing a stand-alone Wildlife Connectivity Element for the General Plan would be the most comprehensive approach. Government Code section 65302(d) also requires the City to incorporate information from a state plan on wildlife connectivity and best available science. To ensure compliance with the requirements of AB 1889, the GPU should incorporate recommendations from scientific sources, such as “Maintaining Ecological Connectivity Across the Missing Middle of the Puente-Chino Hills Corridor,” by Dr.

Wayne Spencer at the Conservation Biology Institute. Dr. Spencer’s report builds on several previous ecological and wildlife movement studies in the Puente-Chino Hills, as well as the general literature on wildlife movement corridors where it applies to this valuable corridor. The report is included as Exhibit B to this letter.

AB 1889 also establishes a statewide framework for wildlife crossings and requires state agencies to prioritize them. SR-57 is a significant wildlife movement barrier between the Chino Hills and Puente Hills systems. Putting language in the GPU related to the need to address this barrier will better position Brea to access Caltrans and/or federal wildlife crossing funds. (The Federal Infrastructure Investment and Jobs Act included $350M for wildlife crossings nationally).

The GPU includes a Wildlife Corridor Map (Figure CR-3), which identifies the Puente-Chino Hills Wildlife Corridor, Major Wildlife Movement Corridors, and also City of Brea
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provides a connectivity ranking (from 1 to 5) for lands along the corridor. Figure CR-3 should be updated to address the following key issues:
1) Major Wildlife Movement Corridors identified as a narrow brown line is misleading. In fact, animal movement is not necessarily along a line but rather broad movement areas. The corridors shown do not appear accurate based on decades of collecting data. For example, wildlife does not travel along Carbon Canyon Road where vehicular traffic would be a constant source of noise and danger. When they have other options, animals generally do not choose to go through a housing development like the map depicts in Olinda Village and the line more accurately belongs farther to the east.

Animals do not travel along Telegraph Canyon in Chino Hills State Park on the same dirt road with cyclists and hikers, as is depicted. As an example, Dr. Paul Beier’s mountain lion study from the mid-1990’s tracked a single animal as it traversed the Puente-Chino Hills Wildlife Corridor (see Exhibit C) and Hills For Everyone has plotted data for M317, a single cougar tracked in 2023 (Exhibit D). Figure CR-3 should be updated with more local information on major movement corridors.
2) Where wildlife cross a road is critically important and missing from the map.

There are no cameras along roadways, so the only way we know where they cross is where they are killed. Hills For Everyone has nearly 50 years of observation and photos for Carbon Canyon Road, and the data shows that wildlife cross at the areas shown as circles on the map included as Exhibit E. Other relevant data could come from Caltrans, Orange County Animal Control Services, or The Road Ecology Center run by Dr. Fraser Shilling at UC Davis. Wildlife Crossing information should be reflected on Figure CR-3.

In addition to including more information to comply with AB 1889, the GPU should also clearly demonstrate compliance with Senate Bill (SB) 1425, which mandates that the General Plan include plans and action programs that address:
1) Equitable access to open space, considering social, economic, and racial equity; 2) Climate resilience and other benefits coordinated with the Safety Element; and 3) Rewilding opportunities to preserve and enhance natural ecosystems.

Specific actions proposed to address these requirements are identified below (in underline). Brea’s General Plan already includes those goals, policies, and actions that are not underlined:

Existing CR Goals
CR-3: The preservation and maintenance of open spaces for nature, resource management, recreation, and scenic enjoyment.

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CR-4: A community where visual resources reflect Brea’s natural beauty and help guide responsible development.

CR-5: A resilient ecosystem that safeguards habitats for biological resources and wildlife.

Existing CR Policies
CR-3.1: Open Space Preservation. Continue efforts to preserve open space lands for purposes of habitat protection, resource conservation, flood hazard management, public safety, and overall community benefit in collaboration with neighboring jurisdictions and other relevant agencies.

CR-3.2: Sensitive Species and Habitats. Support the conservation of sensitive species, plant communities, and wildlife habitats to the maximum extent feasible through open space dedication, creative site design, and other workable actions.

CR-3.3: Hillside Preservation. Continue efforts to conserve sensitive hillside, ridgelines, canyons, and open space areas in accordance with standards set forth in the Brea City Code.

CR-3.4: Mature Vegetation. Encourage all entities involved in development, redevelopment and landscape maintenance to avoid removing mature vegetation.

Promote the inclusion of a variety of sizes of new vegetation in projects to balance initial aesthetic landscape value with the long-term health and sustainability of the landscape.

CR-3.5: Rewilding. Explore rewilding opportunities and other ecological restoration projects aimed at increasing biodiversity and restoring natural processes.

CR-3.6: Open Space Education. Work with State, Federal, and community partners to develop educational and other materials that promote the preservation and conservation of Brea’s natural resources, to the extent practical.

CR-5.7: Wildlife Corridors. Encourage the preservation of critical wildlife corridors and habitat connectivity, including as part of the development review process.

CR-5.8: Urban Canopy. Preserve and expand the urban canopy of trees and vegetation throughout the community to help reduce urban heat, improve air quality, reduce stormwater runoff, enhance aesthetics, and support biodiversity.

Existing CR Actions
CR-3a: Assess development proposals for potential impacts to important geologic and scenic landform features pursuant to the California Environmental Quality Act (CEQA). Require appropriate mitigation measures, including environmentally sensitive site planning and grading, revegetation and open space dedication, for significant impacts. Consider important topographical features, watershed areas, City of Brea
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ridgelines, soils, and potential erosion problems in the assessments. Ensure the new development is compatible to adjacent open space lands.

CR-3b: Reassess the City’s Hillside Zoning Ordinance to minimize the encroachment of new development near areas of open space, especially sensitive areas.

CR-3c: Collaborate with Federal, State, regional, local, non-profit environmental and conservation organizations, and private entities to conserve, protect, and enhance open spaces and natural resources throughout Brea’s Planning Area.

CR-4a: Assess development proposals, including those in Brea’s SOI, for potential impacts to important visual resources pursuant to CEQA. Require appropriate mitigation measures for all significant impacts. Consider important ridgelines, creeks, open space, views of the surrounding hillsides, and light and glare effects.

CR-4b: Maintain and apply existing design standards to preserve views, vistas, and defining natural features along prominent roadways and visually sensitive areas.

CR-5a: Maintain a buffer area between natural waterways and urban development to protect water quality and riparian areas, as deemed necessary.

CR-5d: Work with local, regional, State and Federal partners to seek funding for wildlife corridor improvements such as dry wedges, culverts, overcrossings at priority locations with high instances of roadkill.

CR-5e: Evaluate the potential to implement a Dark Sky ordinance or other similar regulatory mechanism.

CR-5f: Continue to maintain the City’s tree inventory and use it to periodically identify areas where the urban canopy can be expanded and prioritize these areas for new tree plantings. Establish an inventory-based citywide street-tree lifecycle program with the following elements:
• Prune street trees on a 3–5 year cycle and reserve annual funds for removal/succession planting with the goal of a “No Net Loss” urban canopy standard.
• Establish a citywide tree canopy target. The target measurement should be set to be a measurable improvement over existing conditions and should establish annual planting quotas to meet the target.
• Prioritize street tree planting in the census tracts identified as low-income on Figure CD-5, with annual Council reporting.
• Require tree replacement ratios of greater than 1:1 for both public and private property street tree removals.

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Proposed Additional Actions:

Limit the extension of public services and utility infrastructure into the City’s SOI (water, sewer, roadways) to reduce increasing fire risks and minimize other environmental impacts.

Establish standard conditions of approval (or establish and apply Wildlife Overlay Zoning) to subdivision/zoning approvals to require measures that will help ensure the implementation of measures to maintain connectivity and permeability for wildlife movement. There are many useful standards that should be adopted, including:
• Cluster development, including building pads and driveways, to minimize the perimeter edge of the neighborhood. Require the remainder of the parcel to be protected in an open-space/conservation easement that connects to off-site open space; no fences, structures, night lighting, or turf within the easement area;
• Dark-Sky Lighting. Full cutoff, motion-activated where feasible; 0.1 footcandle maximum at the open space border.
• Bird-Safe Design. For façades within 300 ft of open space, treat at least 90% of glazing with patterns, and prohibit reflective glass.
• Mechanical Noise. Locate HVAC/pool equipment away from open space and enforce a maximum noise volume of 45 dBA at the property line. • Wildlife-Permeable Fuel Modification Plans. Wildfire-safe fuel modification zones must maintain visual cover (allow patches 2-3 feet in height) and avoid complete denudation.
• Establish standards for wildlife-safe barriers and fencing adjacent to open space that requires a minimum of 50% permeable fencing (no continuous solid walls) with a minimum of 6 inches of ground clearance and that restrict grading/retaining walls that block known wildlife corridors.

Require that any project proposed within an identified wildlife movement corridor shall be subject to a Wildlife Movement Impact Analysis prepared by a qualified wildlife biologist, demonstrating that the project will maintain or enhance corridor function.

Identify and prioritize locations where roads, drainage channels, and other linear infrastructure fragment wildlife movement corridors within the City limits or SOI.

The City shall: (a) include wildlife crossing feasibility in all future road design, improvement, or reconstruction projects on roads crossing or adjacent to identified wildlife corridors; (b) require development projects that widen or realign roads in City of Brea
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corridor areas to fund wildlife crossing infrastructure proportional to their impact; and (c) coordinate with Caltrans on SR-57 and SR-142 crossings.

Require that all fuel modification plans within mapped Fire Hazard Severity Zones (FHSZs) be prepared to: (a) map all sensitive vegetation communities within the proposed fuel modification zone; (b) identify the minimum modification footprint necessary to achieve the required fire protection standard for each zone band; (c) specify that native, fire-resistant, locally-appropriate species be used in all replanting areas; and (d) demonstrate that the cumulative habitat removal for the project does not exceed the minimum necessary to achieve the adopted fire protection standard.

When resurfacing or replacing culverts within known wildlife corridors or habitat linkages, upgrade to wildlife-passable crossings and add guiding fencing and native vegetation.

Ensure that at least 90% of residents live within a 10-minute walk (½ mile) of a park or publicly accessible open space, prioritizing disadvantaged or under-served neighborhoods or census tracts identified as low-income on Figure CD-5.

Require universal design, wayfinding, shade/heat relief, and fee-free programming in communities with the greatest park gaps.

In addition to identifying additional public open space in the City’s denser areas as development intensifies, prohibit conversion of parks/open space serving disadvantaged or under-served neighborhoods without replacement of equal or better quality/access so that there is no net loss of community open space.

Prioritize nature-based solutions (floodplain reconnection, wetland/creek restoration, urban tree canopy, cool pavements) to minimize/mitigate flood, heat, wildfire, and drought risks. (Cross-reference to Public Safety Element) Establish a Rewilding and Ecological Restoration Program that identifies, prioritizes, and implements habitat restoration projects on public and private lands to increase biodiversity, restore native species, and reconnect fragmented ecosystems.

Specify locally native, drought-tolerant plant palettes; prohibit invasive species in public landscapes; encourage reintroduction of keystone/native pollinator habitats where feasible. No trees or other plant species that are on the California Invasive Plant Council (Cal-IPC) Invasive Plant list or on their “watch list” for invasiveness are permitted.

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C. Policy Direction in the Public Safety (PS) Element.

The Public Safety Element has a section on Climate Change and Resiliency Planning, which recognizes that the City of Brea can implement policies at the local level to help the community adapt to climate change. See GPU at 211. However, the City must adopt further policies and actions for it to create “A community resilient to changing environmental patterns, including severe weather events and other adverse effects on public health, well-being, and safety,” as stated by Goal PS-5.

Hills For Everyone’s concerns about the issues covered in the PS Element are as follows:
• Urban tree canopy is mentioned but no quantified target is provided. The GPU sets no specific canopy coverage goal, no urban heat island reduction target, and no implementation program with budget or timeline for expanding the tree canopy.

Urban greening can be a significant climate resilience tool. • The GPU mentions maximum feasible beneficial use of stormwater, but there are no green infrastructure standards for new development (e.g., minimum bioswale or permeable paving requirements), no LID requirements beyond baseline NPDES, and no policy explicitly linking stormwater management to climate adaptation. • No urban cooling targets or standards for heat island mitigation. Given the intensity of Southern California heat events and the documented urban heat island effect in developed flatlands adjacent to natural areas, the plan should include cool pavement, cool roof, and urban shade standards for new development. • Climate-adaptive landscaping is not sufficiently specified. The GPU requires “native, non-invasive landscaping” but does not require climate-adaptive species selection, does not address phasing out non-native turf, and does not connect landscaping requirements to the water supply assessment (PEIR Appendix M) or to expected future precipitation variability.

Existing PS Policies
PS-1.10: Standards for New Development. Require ongoing brush management, fuel management/modification defensible space, fire resistant landscaping, visible home and street addressing and signage, and other project design features for new development located in High and Very High Fire Hazard Severity Zones as part of the review process.

PS-2.2: Hillside Development. In areas subject to the City’s Hillside Zoning Ordinance, require a full site-specific geologic study to consider effects of the proposed development on adjacent upslope and downslope areas as well as on the site itself.

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PS-3.9 Open Space Area. Preserve open space areas for flood mitigation when possible.

PS-5.11: Extreme Heat Vulnerabilities. Encourage new developments, major remodels, and redevelopments to address urban heat island issues and reduce urban heat island effects for the proposed project site and adjacent properties.

PS-6.6 Emergency Evacuation Routes and Access. Work with the Fire Department and Police Department to define minimum standards for evacuation of residential areas, particularly in HFHSZs and VHFHSZs, and to maintain, update, and regularly exercise emergency access, protocols, and evacuation routes to assess their effectiveness under a range of emergency scenarios. If areas with inadequate evacuation routes are identified develop appropriate mitigation measures, improvement plans, or education programs to ensure safe evacuation.

Existing PS Actions
PS-1d: Assess site constraints when considering land use designations near wildlands to avoid or minimize wildfire hazards as part of a land use update or amendment.

PS-6g: When evaluating public safety impacts of new developments, the methodology shall consider the following at minimum; however, the City may allow alternate methodology on a case-by-case basis:
• Service Demand Units (SDUs) estimated by land-use type and intensity • Population/employee growth and special risk factors (e.g., WUI, hazardous occupancies, vertical development)
• Network travel-time isochrones and station coverage impacts relative to public safety Service Level Objectives (SLOs)
• Unit-Hour Utilization (UHU) and workload balancing by company • Facility/apparatus/staffing triggers when thresholds are exceeded Proposed Additional Actions:

Adopt a Heat and Air Quality Improvement Plan that contains:
• Cool Pavement standards and pavement resurfacing with shade tree/street tree planting quotas per linear mile.
• Cooling networks with shaded routes and designated cooling centers. • Subsidies or incentives for cool walls and cool roof retrofits. • Methods to integrate metrics for minimizing heat impacts into capital improvement programming.

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III. The Draft Program EIR Biological Resources Mitigation Measures Must Be Strengthened.

The PEIR’s finding of potentially significant impacts obligates the City to adopt legally adequate mitigation measures, and CEQA requires all mitigation measures be adopted simultaneously with, or prior to, Project approval. Mitigation measures may not be deferred when their effectiveness is uncertain or when deferral would prevent the EIR from disclosing the potentially significant impacts of those measures. Sacramento Old City Ass’n v. City Council of Sacramento, 229 Cal.App.3d 1011, 1027-29 (1991).

Uncertainties regarding the mitigation of impacts must be resolved before a lead agency may make the required CEQA findings; an agency may not rely on mitigation measures of uncertain efficacy or feasibility. Kings County Farm Bureau v. City of Hanford, 221 Cal.App.3d 692, 727 (1990). An agency may defer preparation of a plan or completion of a study only when the agency commits itself to satisfying specific performance standards that will ensure avoidance of any significant effects. Id.

Several of the proposed mitigation measures in this PEIR need additional specificity and performance standards to ensure they are fully enforceable and effective at reducing impacts to less-than-significant levels; particularly with respect to wildlife connectivity and hillside habitat areas. The following recommendations are offered to strengthen the clarity, enforceability, and ecological effectiveness of the mitigation framework.

A. Clarify and Strengthen Pre-Construction Survey Requirements.

Mitigation measures requiring pre-construction biological surveys (MM BIO-1, -2, -3, -6, and -7) should be revised to establish minimum survey protocols, including: 1) the specific types of surveys that are required (general biological survey, focused species surveys, jurisdictional delineations), and 2) identifying seasonal timing requirements tied to species detectability. The measures should also specifically require that surveys be conducted prior to any site disturbance, including grading, vegetation clearing, or fuel modification (as opposed to the current “before construction” language that exists in some measures), require that survey results be documented in a report submitted to and approved by the City prior to issuance of grading permits, and, where sensitive resources are identified, the measures should require mandatory avoidance and minimization to the maximum extent feasible, rather than leaving such determinations to later discretionary judgment.

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B. Establish Clear Performance Standards for Habitat Protection and Replacement.

Where impacts to sensitive habitats (e.g., riparian areas, coastal sage scrub, or other native vegetation communities) may occur, mitigation measures should be revised to include: 1) quantifiable mitigation ratios (e.g., 2:1, 3:1, or higher depending on habitat sensitivity); 2) clear requirements that mitigation lands be located within the same ecological region, functionally equivalent or superior in habitat value, and protected in perpetuity through conservation easements or similar mechanisms; and 3) metrics for evaluating the success of restoration efforts that include the minimum amount of native plant cover and the required monitoring duration (e.g., 5–10 years or until success criteria are met).

C. Strengthen Measures Protecting Wildlife Movement and Connectivity.

To ensure the long-term preservation of wildlife movement and connectivity corridors, MM BIO-1 should be revised to more clearly detail the requirements of “an evaluation of potential local and regional wildlife movement corridors” (PEIR at 4.3-60).

The measure should specifically require that discretionary projects avoid siting development within identified or potential wildlife movement corridors to the maximum extent feasible. Where avoidance is not feasible, the measure should require maintenance of minimum corridor widths based on best available science, the use of wildlifepermeable fencing (e.g., avoidance of solid walls), minimizing lighting adjacent to corridors, and the installation of wildlife overcrossings or properly-sized undercrossings where roads intersect movement areas.

D. Limit Reliance on Future Discretionary Determinations.

Several mitigation measures currently rely on phrases such as “if determined necessary” or “as appropriate.” While some flexibility is appropriate at the program level, the measures would be strengthened by identifying specific triggers for when mitigation is required and defining minimum required actions. Furthermore, to ensure long-term effectiveness, mitigation measures should include any ongoing monitoring requirements, annual reporting to the City if appropriate, and adaptive management provisions, requiring corrective actions if the performance standards identified in the mitigation measures are not met. By incorporating clear performance standards, reducing reliance on future discretionary determinations, and strengthening protections for wildlife connectivity—particularly in hillside areas—the City can enhance both the environmental outcomes and the overall defensibility of the PEIR.

City of Brea
March 30, 2026

Page 18 ends

In addition to the points raised above regarding the mitigation measures, we also point out two corrections that should be made to PEIR Figure 4.3-5 (Wildlife CorridorNCCPs Map): the Shell/Metropolitan Water District HCP and the Orange County Transportation Authority NCCP/HCP should both be added to the figure. A map of the Shell/MWD HCP is included as Exhibit F and the OCTA NCCP/HCP is included as Exhibit G.

IV. Conclusion
The proposed GPU and BCSP are an important opportunity for Brea to commit to actively discouraging development in hillside areas within the Brea’s Sphere of Influence, emphasizing both fire safety and wildlife protection at the urban edge, bringing the General Plan into compliance with new State laws that prioritize wildlife corridors and habitat connectivity, and supporting urban greening and climate resiliency. The development envisioned in the GPU and BCSP will have significant impacts, and implementing the policy suggestions and mitigation measure revisions in this letter will serve to ameliorate those effects and provide a benefit to all of Brea.

Please notify Hills For Everyone and this office of the release of the Final GPU/BCSP and the Final PEIR, and provide us all notices for any hearings, staff reports, briefings, meetings, and other events related to the Project.

Respectfully yours,

SHUTE, MIHALY & WEINBERGER LLP
Edward T. Schexnayder
cc: Claire Schlotterbeck, Hills For Everyone

Exhibits:

A: Confirmation receipt of September 24, 2025 NOP comment letter submittal.

B: Maintaining Ecological Connectivity Across the “Missing Middle” of the PuenteChino Hills Wildlife Corridor, prepared by Dr. Wayne D. Spencer of the Conservation Biology Institute (2005).

C: Coordinates for Cougar Tagged M6, prepared by Dr. Paul Beier, exhibit prepared by Hills For Everyone.

City of Brea
March 30, 2026

Page 19 ends

D: Plotted Data Points for Cougar Tagged M317.

E: Locations of Wildlife Crossing Fatalities, prepared by Hills For Everyone.

F: Shell/Metropolitan Water District HCP map.

G: Orange County Transportation Authority NCCP/HCP map. 2045394.1
Exhibit A
1 Kristi Bascom
From: Brea2050 <[email protected]>
Sent: Wednesday, September 24, 2025 8:46 PM
To: Kristi Bascom
Cc: [email protected]; Schlotterbeck, Claire; Edward T. Schexnayder; Brea2050 Subject: RE: CEQA Comments for Brea 2050: Focused GPU and BCSP Hello,
This is to acknowledge the receipt of the NOP comments.

Thank you.

Please click 2025 Calendar for City Service Hours/Alternate Fridays Closed.

From: Kristi Bascom <[email protected]>
Sent: Wednesday, September 24, 2025 2:06 PM
To: Brea2050 <[email protected]>
Cc: [email protected]; Schlotterbeck, Claire <[email protected]>; Edward T. Schexnayder <[email protected]>
Subject: CEQA Comments for Brea 2050: Focused GPU and BCSP Dear City of Brea Planning StaƯ,
On behalf of our client, Hills For Everyone, we submit the attached comment letter on the Notice of Preparation (NOP) for the forthcoming EIR on the City of Brea’s Focused General Plan Update (GPU) and Brea Core Specific Plan (BCSP).
2 Please confirm that this email has been received and inform me directly if you have any trouble accessing the attached PDF.

Kind regards,
Kristi Bascom
Kristi Bascom, AICP
Urban Planner
Shute, Mihaly & Weinberger LLP
396 Hayes Street
San Francisco, CA 94102-4421
o: 415/552-7272 x 202 c: 925/872-6327
www.smwlaw.com | A San Francisco Green Business
Exhibit B
Maintaining Ecological Connectivity
Across the “Missing Middle”
of the
Puente-Chino Hills Wildlife Corridor
Final Report
July 2005
The Conservation Biology Institute provides scientific expertise to support conservation and recovery of biological diversity in its natural state through applied research, education, planning, and community service.

Maintaining Ecological Connectivity
Across the “Missing Middle”
of the
Puente-Chino Hills Wildlife Corridor
Final Report
Prepared by:

Wayne D. Spencer, Ph.D.
815 Madison Avenue
San Diego, CA 92116
Prepared for:

Resources Legacy Fund Foundation
555 Capitol Mall, Suite 650
Sacramento, CA 95814
July 2005
Puente-Chino “Missing Middle” Analysis
Conservation Biology Institute ii July 2005
Table of Contents
Page
Acknowledgements ................................................................................................................ iv Executive Summary.................................................................................................................v Methods................................................................................................................................v Results............................................................................................................................... vii Discussion.......................................................................................................................... ix Conclusions and Recommendations ....................................................................................x Introduction..............................................................................................................................1 Report Objectives.................................................................................................................2 Study Area ................................................................................................................................4 Biogeography.......................................................................................................................4 Previous Studies...................................................................................................................4 Methods...................................................................................................................................10 Reconnaissance..................................................................................................................10 Target Species....................................................................................................................11 Defining Geographic Units, Barriers, and Filters ..............................................................14 Analyses — Assessing Existing and Future Functionality................................................18 Results .....................................................................................................................................20 Functionality of Geographic Units.....................................................................................20 Summary of Overall Corridor Function.............................................................................31 Future Corridor Functions..................................................................................................35 Discussion................................................................................................................................40 Functions and Benefits of Wildlife Corridors....................................................................40 Assessing Connectivity Pros and Cons..............................................................................40 Mitigating Road Effects.....................................................................................................43 Conclusions and Recommendations.....................................................................................45 Conservation and Restoration Priorities for the Missing Middle ......................................45 References Cited.....................................................................................................................49 Puente-Chino “Missing Middle” Analysis
Conservation Biology Institute iii July 2005
Page
Maps
Map 1. Study area showing the Missing Middle of the Puente-Chino Hills Wildlife Corridor................................................................................................3 Map 2. Geographic units of the Puente-Chino Hills Wildlife Corridor……………... 15 Map 3. Conservation and restoration priorities in the vicinity of Missing Middle...... 46 Figures
Figure 1. The Puente-Chino range of hills juts into the heavily urbanized Los Angeles Basin from the tip of the Santa Ana Mountains range……………………...… 1 Figure 2. View northwest across Coal Canyon Wildlife Underpass…......................... 23 Figure 3. View northeast across Tonner Bridge and Highway 57…………………….. 25 Figure 4. View northwest across Segment 3 and Harbor Boulevard to Segment 4, indicating general trends in wildlife movements……………………………. 27 Figure 5. Conceptual development plan for the Shell-Aera Master Planned Community………………………………………………………………… 35
Figure 6. Aerial photograph showing City of Industry’s proposed Tres Hermanos reservoir and new road in Tonner Canyon…………………………………... 37 Photos
Photo 1. View east under the Tonner Bridge…………………………………………. 26 Photo 2. View southeast across the Harbor Boulevard “deathtrap”…………………. 28 Tables
Table 1. Summary of previous studies of wildlife populations and movements in the Puente-Chino Hills study area………………………………………………... 5
Table 2. Characteristics of geographic units comprising the Puente-Chino Hills Wildlife Corridor……………………………………………………………. 21
Table 3. Characteristics of roads crossing the Puente-Chino Hills Wildlife Corridor... 22 Table 4. Functional classification of geographic units for supporting target species populations and movements…………………………………………………. 33
Puente-Chino “Missing Middle” Analysis
Conservation Biology Institute iv July 2005
Acknowledgements
Conservation Biology Institute (CBI) thanks the following individuals and organizations for support and contributions to this report. Financial support was provided by Resources Legacy Fund Foundation, with special thanks to Maureen Rose and Ed Hastey. Rick Rayburn (California State Parks) was responsible for involving CBI in this important project and provided early guidance on its goals. Claire Schlotterbeck (Hills For Everyone) provided essential information, advice, contact information, and inspiration, and Melanie Schlotterbeck (The Trust for Public Land) provided GIS data, photographs, advice, information, contacts and other valuable input. Dan Wooldridge (Waters and Faubel) provided copies of various reports and plans reviewed in this report. Andrea Gullo and Amy Henderson (Puente Hills Landfill Native Habitat Preservation Authority) also provided data, reports, and other useful information. Geary Hund, Claire Schlotterbeck, Melanie Schlotterbeck, and Amy Henderson reviewed a draft of this report and offered valuable corrections and clarifications to the contents. The following CBI employees assisted in preparing this report: Heather Rustigian, with oversight from Jim Strittholt, prepared GIS maps and calculations; John Bergquist provided Keyhole screen captures used as illustrations; and Mike White and Jerre Stallcup reviewed and helped produce the report.

Puente-Chino “Missing Middle” Analysis
Conservation Biology Institute v July 2005
Executive Summary
The Puente-Chino Hills Wildlife Corridor is a peninsula of mostly undeveloped hills jutting about 42 km (26 miles) from the Santa Ana Mountains into the heart of the densely urbanized Los Angeles Basin. Intense public interest in conserving open space here has created a series of reserves and parks along most of the corridor’s length, but significant gaps in protection remain.

These natural habitat areas support a surprising diversity of native wildlife, from mountain lions and mule deer to walnut groves, roadrunners, and horned lizards. But maintaining this diversity of life requires maintaining functional connections along the entire length of the corridor, so that wildlife can move between reserves—from one end of the hills to the other.

Already the corridor is fragmented by development and crossed by numerous busy roads, which create hazards and in some cases barriers to wildlife movement. Proposed developments threaten to further degrade or even sever the movement corridor, especially within its so-called “Missing Middle.” This mid-section of the corridor system, stretching from Tonner Canyon on the east to Harbor Boulevard on the west, includes several large properties proposed for new housing, roads, golf courses, and reservoirs. Such developments would reduce habitat area and the capacity to support area-dependent species and, if poorly designed, could block wildlife movement through the corridor.

This report builds on an impressive array of previous ecological and wildlife movement studies in the Puente-Chino Hills, as well as the general literature on wildlife movement corridors as it applies to this unique peninsula of wildness. It supplements the existing information with an analysis of gaps in protection—with special focus on the vulnerable Missing Middle—and recommends conservation and management actions to prevent further loss of ecological connectivity and retain native species.

Methods
I performed a meta-analysis of corridor function using existing scientific information on the distribution and movement patterns of wildlife species in the study area, as supplemented by field reconnaissance and examination of aerial and satellite imagery. Following the lead of previous researchers, I segmented the range of hills into nine geographic units by roads and other breaks in habitat contiguity. From southeast to northwest these are:
• A biological “core” area (defined below), represented by the Santa Ana Mountains; • Seven segments of the functional Puente-Chino Hills Wildlife Corridor (from southeast to northwest: 1-Chino, 2-Carbon-Tonner, 3-Shell-Aera, 4-Powder-Schabarum, 5-San Miguel, 6-East Whittier, 7-West Whittier); and
• One isolated patch off the tip of the range of hills (Whittier Narrows), which is effectively disconnected from the functional corridor segments by major roads and urban barriers.

Puente-Chino “Missing Middle” Analysis
Conservation Biology Institute vi July 2005
The Missing Middle consists of the western portion of Segment 2 (including the large and biologically diverse Tonner Canyon) and all of Segment 3 (Shell-Aera property and adjacent lands between Highway 57 and Harbor Boulevard). The eastern portion of Segment 2 (between Tonner and Carbon Canyons) is largely conserved already, but Tonner Canyon and Shell-Aera are unprotected and threatened by development projects.

Each of the nine geographic units was initially characterized for how it appears to function in supporting populations of target species, including mountain lion, mule deer, bobcat, coyote, coast horned lizard, and greater roadrunner, as well as in the richness of its reptile and amphibian community. The following coarse-scale definitions apply to these units:
• Core areas must be larger than 2,000 sq. km and capable of supporting a population of 20 adult mountain lions (the most area-dependent target species). Due to large size and relatively low “edge effects,” a core area will support the greatest diversity of species and should support populations of all target species. The Santa Ana Mountains are the only core in the study area. This core serves as a source for mountain lions and other species to enter the corridor system.
• Subcores are smaller (but at least 60 sq. km) and capable of supporting a population of bobcats, the second-most area-dependent target species. Subcores can sustain populations of most target species and have moderate to high species diversity. Corridor Segment 1 (Chino Hills between Highways 91 and 142) is the only subcore, although Segment 2 appears to function as an extension of this subcore, as discussed below. • Patches are smaller than 60 sq. km, but may support small numbers of bobcats and significant populations of other target species. Patches may also provide significant livein or move-through habitat for mountain lions and bobcats, whose home ranges may cover multiple geographic units. Most segments in the corridor system are patches, but they vary greatly in size (from about 1.5 to 44.3 sq. km), vegetation composition, isolation by roads, and ability to support target species.

The roads delimiting these segments were next characterized for their effects on target species movements—as barriers, semi-permeable “filters,” or highly permeable filters. Based on the scientific literature and field reconnaissance, each road was assessed for how easily target species can cross it, the availability and effectiveness of crossing structures (e.g., bridges and underpasses), and relative frequency of roadkill. Roads considered highly permeable to wildlife movement allow adjacent segments to function as one larger segment, such that two areas originally classified as separate patches may effectively serve as one larger patch (summing the area of adjacent units), or even a subcore, for certain target species.

I assigned each newly defined unit, or composite unit, a function relative to supporting individuals or populations of each target species based on unit size, habitat composition, and other factors, as follows:

Puente-Chino “Missing Middle” Analysis
Conservation Biology Institute vii July 2005
• Population — capable of supporting a breeding population of at least 20 adults and potentially serving as a source of individuals that disperse into other units. • Subpopulation — capable of supporting at least two but less than 20 breeding individuals.

Subpopulations may exchange individuals with other areas within a larger metapopulation (a set of partially isolated populations linked by occasional dispersal) and may provide individuals to recolonize habitat patches in case of local extirpation. • Home Range Part — incapable of supporting at least two breeding individuals on its own, but may provide live-in habitat (e.g., foraging or resting cover) and form a part of one or more individuals’ home range(s).
• Move-through — not contributing significant live-in habitat for a species as part of a functional home range, but capable of accommodating movements between more substantial units within a home range, or potentially used for dispersal between other habitat units.

This system for characterizing geographic units and movement impediments was used to assess how the overall corridor system functions to support target species, and how these functions might change with potential development scenarios, such as new roads or housing that could add movement barriers or reduce wildlife carrying capacity in corridor segments.

Results
Existing Corridor Function
The Puente-Chino Hills Wildlife Corridor appears functional for at least larger mammals and birds, although tenuously so in the Missing Middle (due to several barrier or near barrier roads) and across smaller Segments 4 and 5 (due to their small size, strong edge effects, and high human and pet activity). Essentially all roads in the study area are considered barriers or at least strong filters to movements by many reptiles, amphibians, and small mammals; however, most birds and larger mammals currently can move between all segments either at-grade (with mortality risks) or via critical road-crossing structures. Despite many crossing constraints through the corridor, especially in and just west of the Missing Middle, target species are confirmed or highly likely to occur in all seven Puente-Chino Hills corridor segments, except for coast horned lizard, which may already be absent (or will disappear in the future) west of Highway 57.

Individual mountain lions are capable of traversing the length of the corridor, albeit at some risk of roadkill, and one or more lions still hunt as far west as the western Puente Hills (known locally as the Whittier Hills). Most other target species (e.g., bobcats, roadrunners) appear to persist throughout the corridor as metapopulations that are connected genetically and demographically by at least occasional dispersal between geographic units.

Carbon Canyon Road (between Segments 1 and 2) and Turnbull Canyon Road (between Segments 6 and 7) are considered highly permeable to at least larger mammals and birds, so I Puente-Chino “Missing Middle” Analysis
Conservation Biology Institute viii July 2005
merged Segments 1 and 2 to form a larger Chino-Tonner subcore, and I merged Segments 6 and 7 to form a larger Whittier Hills patch. The most critical road-crossing structures are the Coal Canyon Wildlife Underpass (connecting the Santa Ana Mountains Core to the Chino Hills under Highway 91); a box culvert under Carbon Canyon Road known to be used by bobcat and other species; the Tonner Canyon Bridge on Highway 57 (the only viable crossing beneath this busy freeway for deer, mountain lion, bobcat, and other species); and the Colima Service Tunnel (used by bobcat, deer, coyote, and other species to cross under Colima Road between San Miguel Canyon and the Whittier Hills). In addition, a new wildlife tunnel is being built under Harbor Boulevard (between Segments 3 and 4) at a location well-documented as a roadkill “death trap.” There appears to be a gradient of declining amphibian and reptile diversity and evenness moving west from the Chino Hills, probably due to increasing edge effects coupled with increasing distance and number of barriers and filters that must be crossed the farther west one moves from source habitats in the east. A similar gradient may exist for other taxa, such as small mammals, that are similarly limited in their dispersal abilities.

Given the length of the corridor relative to species movement abilities, the capacity of corridor segments to support many species depends both on
• The potential for individual movement between each set of adjoining segments (a function of roads and road-crossings), and
• Having sufficient live-in habitat along the way to support populations or subpopulations that contribute dispersing individuals.

The greater a segment’s distance from units supporting populations or subpopulations of a species, the lower the probability that the segment can continue supporting a species. If the distance between occupied segments becomes too great, or if barriers prevent inter-segment movement, local extinctions are inevitable in the isolated segments. Thus, any reduction in the capacity of segments to support populations or subpopulations increases the probability of local extinctions in that segment, as well as in all other “downstream” segments to the west.

Habitats in the Missing Middle are critical to maintaining overall corridor function. The Tonner Canyon area serves as an extension of the large Chino-Tonner subcore, with significant live-in habitat that can contribute dispersing animals to move into other segments. Likewise, Segment 3 (Shell-Aera) presumably supports significant numbers of target species that disperse (currently at some risk) across Harbor Boulevard into Powder Canyon (Segment 4) and beyond.

Future Scenarios
I assessed the likely effects of several proposed development projects in the Missing Middle on species persistence through the corridor system. This qualitative assessment uses the conceptual model developed above, based on how projects might affect the capacity of geographic units to support populations or individuals and the ability of individuals to cross between units. The projects include a new residential community, a series of reservoirs, and a major new road.

Puente-Chino “Missing Middle” Analysis
Conservation Biology Institute ix July 2005
All three proposed developments have the potential to extirpate target species from large portions of the Puente-Chino Hills Wildlife Corridor. By impeding species movements or metapopulation dynamics, a project’s impacts on species persistence may extend far beyond project boundaries, potentially rippling through the range of hills to eliminate wildlife populations as far west as the Whittier Hills (10-12 km west of the Missing Middle). The proposed Shell-Aera Master Planned Community would seriously degrade the ability of Segment 3, and all segments farther west, to support target species, especially mountain lion and bobcat.

This would have cascading effects on flora and fauna in all segments from this point west.

A plan by the City of Industry to build three water reservoirs in Tonner Canyon could also have substantial adverse impacts on corridor function. Although a reservoir or other development in upper reaches of Tonner Canyon might not greatly affect corridor function, any development in middle and especially lower Tonner Canyon could have severe impacts on corridor function, especially if wildlife use of the Tonner Canyon Bridge (to cross Highway 57) is reduced. Any development that blocks access through the bridge area would make Highway 57 a complete barrier to many species and would likely lead to wildlife extirpations in segments farther west.

At the very least, creation of these reservoirs would reduce the size of the Chino-Tonner subcore and its capacity as a source of animals that disperse into the rest of the corridor system.

Finally, plans by the City of Industry to build a new road running the length of Tonner Canyon could split the Chino-Tonner subcore in two, potentially isolating about 21.2 sq. km of habitat from this currently large and contiguous source habitat. The road would probably require major cut and fill to construct and could render disfunctional the critical Tonner Bridge wildlife undercrossing. This would almost surely result in the rapid loss of mountain lion and bobcat from more westerly segments, with cascading effects through the ecological community. Deer and other species would also likely disappear from westerly segments over a longer time period.

A full impact analysis for any of these proposed projects should address cumulative impacts on wildlife populations and movements through the corridor. Among these cumulative impacts would be inducement of further development, such as additional residential, commercial, or industrial development along the road. Increases in traffic and roadkill should also be analyzed and mitigated for. Any combination of two or more of these projects, even if well designed, would likely render the Puente-Chino Hills Wildlife Corridor non-functional west of Chino Hills State Park, regardless of mitigation.

Discussion
The scientific literature on the functions and values of wildlife corridors is huge and growing.

Movement corridors connecting reserves or larger “core areas” of habitat have been documented to counter many adverse effects of isolation by fragmentation on species and ecological processes. Some critics have argued that there are costs as well as benefits to conserving corridors and that, under certain circumstances, creating or maintaining corridors could harm some species or communities. However, the overwhelming weight of scientific evidence is that maintaining connectivity is beneficial, especially for those species and ecological communities Puente-Chino “Missing Middle” Analysis
Conservation Biology Institute x July 2005
for which connectivity “is the natural state of things.” Most arguments against corridors boil down to nothing more than cautions against viewing them as conservation panaceas.

Nevertheless, I reviewed the following arguments made against corridor conservation as they apply to the Puente-Chino Hills Wildlife Corridor:

1. Corridors may serve as conduits for the spread of deleterious species;

2. Corridors may spread detrimental processes, such as wildfire or disease, among reserve areas;

3. Corridors may facilitate movements by highly mobile and adaptable animals (like coyotes), but may not help more sedentary or at-risk species;

4. Corridors could attract wildlife into edge-affected habitats with high mortality rates; and

5. Corridor conservation may be more expensive or less beneficial than other options, such as increasing the size or management of core reserves.

Critical review of these concerns for the Puente-Chino Hills Wildlife Corridor finds them irrelevant or insignificant in this case; at least, the biodiversity benefits of conserving the corridor far outweigh any potential for harm.

Mitigating the adverse effects of roads, including barrier effects and increased mortality, is essential to maintaining corridor functions. The scientific literature on effective mitigation actions, especially wildlife road-crossing structures, is also large and growing, with many success stories. The main types of structures, from most to least effective, are vegetated landbridges (wildlife overpasses), bridges, underpasses, and culverts. Vegetated overpasses are quieter than underpasses, maintain ambient conditions, seem less intimidating for some species than dark tunnels, and have proven highly successful in the U.S., Canada, and Europe for a wide variety of wildlife species. Bridges are also highly effective, especially if wide and open with natural vegetation growing beneath, such as under the Tonner Bridge. Culverts and other tunnellike structures can be effective for some species, but only very large culverts (such as box culverts and equestrian tunnels) are effective for larger mammals. Earthen flooring is preferable to concrete or metal. Regardless of crossing type, wildlife fencing is crucial for keeping animals off the road and for funneling them toward the crossing structure. Vegetative cover near the entrances also increases wildlife use of crossing structures.

Conclusions and Recommendations
Given the huge investment already made to maintain the Puente-Chino Hills Wildlife Corridor, additional conservation investment in the Missing Middle seems not only prudent, but essential if society believes the continued presence of deer, bobcats, roadrunners, and other wildlife is desirable in this unique peninsula of wild in a sea of development. My recommendations for how to do this are largely concordant with previous recommendations by other biologists.

I recommend conserving all of Segment 3 (the Shell-Aera property) and at least the middle and lower portions of Tonner Canyon, including prohibiting any new road or other development that Puente-Chino “Missing Middle” Analysis
Conservation Biology Institute xi July 2005
would fragment this critical habitat block or degrade in any way the utility of the Tonner Bridge as a wildlife underpass. I also emphasize the following recommendations for improving roadcrossing structures and reducing roadkill.

B. Prohibit any development that would increase traffic under the Tonner Bridge or add any new impediments (structures, lights, noise, etc.) to the vicinity of the bridge. Restore riparian vegetation along Tonner Creek, where degraded by oil development activities.

Fence along Highway 57 if monitoring suggests road mortality is high.

C. Secure rights to install wildlife fencing along both sides of Harbor Boulevard to reduce roadkill and ensure maximum utility of the wildlife tunnel being built here. Plant screening vegetation on either side of the tunnel to provide cover to wildlife approaching the entrances.

D. Secure remaining “at-risk” parcels in the narrow, constricted portion of the corridor between Powder Canyon and Hacienda Boulevard. Enlarge or otherwise improve the existing equestrian tunnel under Hacienda Boulevard to enhance its use by wildlife, including adding screening vegetation on the western end. Add wing fencing on either side of the tunnel to help funnel wildlife to it. Do not fence extensively along Hacienda Boulevard, unless coupled with new crossing structures, because most large mammals currently cross at-grade. Consider building a wildlife overpass (a vegetated wildlife bridge) over Hacienda Boulevard, taking advantage of steep slopes rising up from either side of the road, as mitigation for any future road improvements that would increase traffic volume or speed.

E. Maintain and improve the Colima Service Tunnel as a critical wildlife underpass. Add fencing or screening vegetation if necessary, based on further site-specific inspection or monitoring. Limit actions that would increase disturbance in the vicinity of the Service Tunnel from sunset to sunrise, such as artificial lighting or nighttime traffic or recreational uses through the tunnel.

Puente-Chino “Missing Middle” Analysis
Conservation Biology Institute 2 July 2005
This loss would be doubly unfortunate given the tremendous public investment already made to conserve and restore biological open space and unfettered wildlife movement through this range of hills—from the Coal Canyon wildlife underpass at Highway 91, through Chino Hills State Park, Powder Canyon, Schabarum Park, and other private and public open space dedications to the western end of the Puente Hills (known locally as the Whittier Hills1). According to the California Department of Parks and Recreation, nearly a quarter billion dollars have already been expended or committed to acquiring and restoring natural open space in the Puente-Chino Hills Wildlife Corridor (http://hillsforeveryone.org/state_investment_table.htm). But the benefits of these existing investments is severely threatened by proposed development projects— including new roads, housing developments, golf courses, and reservoirs.

These threats are most urgent in the so-called “Missing Middle” of the corridor—from Tonner Canyon on the east (mostly owned by the City of Industry) to Harbor Boulevard on the west (Map 1). No major reserves are yet established in this broad midsection of the Puente-Chino Hills, and connectivity is threatened by a major new housing development, a proposed road, and a series of new dams and reservoirs that would flood Tonner Canyon. Should one or more of these projects sever functional connectivity, reserves farther west (e.g., Habitat Authority Wilderness Preserve, Powder Canyon, and Schabarum Regional Park, among others) could lose key species and suffer further ecological degradation.

This report reviews available scientific evidence on wildlife movement corridors, reserve design, and local biological resources to define conservation priorities for maintaining connectivity from one end of the corridor to the other. It focuses on the Missing Middle, because this portion is least protected and is at most immediate risk of further degradation. The purpose of this analysis is to identify (a) those portions of the Missing Middle whose conservation would most contribute to continued wildlife movement and ecosystem health throughout the corridor system, and (b) remedial actions that would most improve the situation for native wildlife—such as retrofitting existing roads with wildlife crossing structures to reduce roadkill and improve movement opportunities.

Report Objectives
• Synthesize the science of wildlife movement corridors as it pertains to the Puente-Chino Hills Wildlife Corridor.
• Analyze existing conditions and potential future conditions for the persistence and movement of wildlife populations in the corridor system. • Recommend conservation and management priorities to sustain and improve connectivity through the Missing Middle and hence the greater Puente-Chino Hills Wildlife Corridor.

1 Although “Whittier Hills” is not an official geographic name recognized by the U.S. Geological Survey, the western portion of the Puente Hills is known locally as the Whittier Hills, and previous researchers have used this place name. I therefore also use Whittier Hills to refer to the hills west of Colima Boulevard.

Conservation Biology Institute 3 July 2005
Map 1. Study area showing the Missing Middle of the Puente-Chino Hills Wildlife Corridor.

Puente-Chino “Missing Middle” Analysis
Conservation Biology Institute 4 July 2005
Study Area
This study considers two nested study areas (Map 1): the entire Puente Hills-Chino Hills Wildlife Corridor, extending about 42 km from the Santa Ana Mountains to the San Gabriel River, and the so-called “Missing Middle” of this larger landscape. The Missing Middle is that section of the Puente-Chino Hills Wildlife Corridor from Harbor Boulevard on the west to and including Tonner Canyon on the east. The Missing Middle is largely unconserved and is threatened by a variety of development projects.

Biogeography
The Puente-Chino Hills are the northernmost extension of the Peninsular Mountain Range, which begins in Baja California, Mexico. They are a topographic expression of the 500-km-long Whittier-Elsinore fault system, pushed up between the Whittier and Chino sections of this major slip-shear fault system. The geologically dramatic origins of the hills also contribute to their relatively undeveloped status, because steep slopes, earthquakes, landslides, tar pits, and active and former oil wells have tended to limit development, at least until recently.

The hills rise from the flat Los Angeles Basin, at less than 100 m (300 ft) elevation, to over 540 m (nearly 1,800 ft) at San Juan Hill. The regional climate is mild and Mediterranean, which contributes to the high diversity of species in coastal Southern California. Vegetation in the hills is a mosaic of open grasslands (which have been affected by grazing over the years), coastal sage scrub, chaparral, oak woodlands, riparian scrub, riparian woodlands, and rare California black walnut woodlands—a grossly under-protected resource that could be considered an “endangered habitat.” These communities support flora and fauna relatively typical of the biodiversity in Southern California—which is remarkable given that the hills are entirely surrounded by the largest urbanized area in the U.S.

Previous Studies
The Puente-Chino Hills represent one of the most closely scrutinized and intensively researched wildlife movement corridors in Southern California, if not North America. Its existence and importance are well appreciated by the local populace, with 53% of local residents having “heard of the wildlife corridor in the Puente Chino Hills area” and 83% in favor of maintaining the corridor (51% “strongly” supported this) (Decision Research 2003). The area’s flora, fauna, and ecological functions are well studied, with a number of intensive studies of wildlife distributions and movements covering all or substantial portions of the area (Table 1). In 1994 an entire scientific conference was focused on the biological functions and values of this unique range of hills (Natural Resources in the Puente Hills-Chino Hills Corridor: Implications for Land Use and Planning. A symposium at Whittier College, March 18-19, 1994)2 .

2 Abstracts of papers presented at this conference can be found at http://www.hillsforeveryone.org/PDF Files/whittier college symposium.pdf.

Puente-Chino “Missing Middle” Analysis
Conservation Biology Institute 5 July 2005 Table 1. Summary of previous studies of wildlife populations and movements in the Puente-Chino Hills study area. Reference Target Species Major Focus Study Area Methods Relevant Results Recommendations Robertson et al. 1995 Large mammals
Assess likely movement routes and constraints.

Entire PuenteChino Hills Wildilfe Corridor from the Santa Ana River to the San Gabriel River.

Field reconnaissance, walking the length of the corridor to assess likely movement routes and constraints. Incidental observations of wildlife sign and roadkill.

At least one pathway without complete obstruction existed for large mammals, from the Santa Ana River to the Whittier Hills, in 1994-95, but with several significant constraints. The most critical impediment was Harbor Blvd. and adjacent development. Movement across Interstate 605 to the San Gabriel River (Whittier Narrows Recreation Area) considered “highly improbable.” Conserve land to connect existing reserves (especially in the middle portions of the Corridor); restore native vegetation; retrofit undercrossings at problem roads, especially Harbor Blvd., with tunnels or bridges to reduce roadkill and improve connectivity for large mammals.

Noss et al. 1997
All vertebrate wildlife
Assess importance of Coal Canyon linkage to maintaining viable species populations in the Santa Ana Mountains and Puente-Chino Hills.

Entire PuenteChino Hills Wildlife Corridor and Santa Ana Mountains.

Literature review, field reconnaissance, and analysis of which species’ populations were likely to benefit from protecting and improving the Coal Canyon linkage and underpass.

Coal Canyon is the last viable linkage between the Chino Hills and Santa Ana Mountains. At least 21 vertebrate species have populations <500 individuals in the Puente-Chino Hills, and at least four of these have <50 breeding adults. Risks of extirpation from the hills would increase for all these species in the absence of the Coal Canyon corridor. The corridor also benefits species in the Santa Ana Mountains, especially the mountain lion and several grassland species. Mountain lion and bobcat would likely be the first species adversely affected by loss of the corridor.

Protect and restore a functional undercrossing at the Coal Canyon interchange with Highway 91. Remove pavement and restore natural soils, vegetation, and drainage through the undercrossing, and install wildlife fencing to funnel wildlife off the highway and through the underpass.

Puente-Chino “Missing Middle” Analysis
Table 1. Continued. Conservation Biology Institute 6 July 2005 Reference Target Species Major Focus Study Area Methods Relevant Results Recommendations Haas and Crooks 1999, Haas 2000, Haas and Turschak 2002 Large and mediumbodied mammals
How landscape variables and underpass characteristics affect the distribution and relative abundance of target species in the study area, and the frequency of underpass usage by each species.

Entire PuenteChino Hills Wildlife Corridor, from Santa Ana River to Whittier Hills.

Field methods: scat transects, remote-triggered camera stations, and baited track stations. Statistical analyses:Correlated probability and frequency of species use with landscape variables (e.g., corridor width, % wild) and underpass characteristics.

Bobcat and long-tailed weasel were negatively associated with habitat fragmentation. Fragmentation was negatively associated with probability of underpass usage by coyote, bobcat, and long-tailed weasel, and negatively associated with the frequency of use by bobcat. Underpass dimensions were important in determining probability of use by deer and gray fox, and with frequency of use in coyote, gray fox, deer, and domestic cat, with more open underpasses used most. The amount of natural cover surrounding the underpass entrance was important for bobcat. Fencing and roadway dividers were most effective on coyote use of underpasses. Overall, the probability of an underpass being used depends primarily on landscape characteristics,
while its frequency of use depends primarily on underpass dimensions.

Bobcats are an excellent target species for conservation in the study area. Habitat acquisition and restoration should be concentrated in the narrowest portion of the corridor and at chokepoints along roadways. Existing underpasses should be surrounded by natural cover and use fencing to direct wildlife under the roadway. Future underpasses should be large and situated as far from residential areas as possible.

Puente-Chino “Missing Middle” Analysis
Table 1. Continued. Conservation Biology Institute 7 July 2005 Reference Target Species Major Focus Study Area Methods Relevant Results Recommendations Cooper 2000 Breeding birds Determine distribution of breeding land birds to identify priority conservation areas.

Entire PuenteChino Hills Wildlife Corridor, from Santa Ana River to Whittier Hills.

Point counts and walking transects to determine presence/absence.

California gnatcatcher, cactus wren, and other rare or declining species documented in diverse locations. Greater roadrunner widespread but not common; most commonly observed in middle portions of the Corridor. California quail found throughout study area except smallest fragments. Burrowing owl apparently extirpated from the study area during the 1990s. Several areas of high-quality habitats supporting diverse avifauna identified.

Conserve three priority areas based on size, threats, and support of declining species: (a) coastal sage scrub in northern Brea and Yorba Linda (southern portion of Missing Middle); (b) extensive grassland and savannah south of Rowland Heights (northern portion of Missing Middle); (c) grasslands of upper Tonner Canyon (northeastern portion of Missing Middle).

PCR et al. 2000
General wildlife
Analyze the Puente Hills area as a Significant Ecological Area (SEA) recognized by the County of Los Angeles.

That portion of the study area within Los Angeles County, from the Whittier Narrows to Tonner Canyon.

No original field studies; review and analysis of existing information.

The area meets several designation criteria as an SEA, including that it is regionally important to many resident and migrating species, especially large mammals, wintering raptors, and songbirds, in large part due to regional connectivity.

Retain connectivity and linkage values between major canyons of the SEA, and especially at choke points and major road crossings.

Puente-Chino “Missing Middle” Analysis
Table 1. Continued. Conservation Biology Institute 8 July 2005 Reference Target Species Major Focus Study Area Methods Relevant Results Recommendations Lyren 2001 Coyotes and bobcats
Home range and movement characteristics, roadkill, and underpass use by bobcats and coyotes.

Primarily along SR 71 and adjoining areas occupied
by telemetered
animals.

Radio telemetry (29 coyotes, 4 bobcats); roadkill surveys along SR-71.

Home ranges of about half of all telemetered animals overlapped SR71, indicating frequent road crossing by individuals. Most animals crossing
the road were documented using underpasses; coyotes used underpasses more than bobcats. Coyote use of underpasses seemed suppressed by traffic volume. No bobcats were found road-killed; coyotes frequently were road-killed, with concentrations where no wildlife fencing was present along road.

Wildlife fencing should be used to funnel wildlife to underpasses.

Schlotterbeck 2001
Large and mediumbodied mammals; reptiles and amphibians.

Assemble existing data from Haas and Crooks 1999 and Case and Fisher 1998 into a GIS database.

Entire PuenteChino Hills Wildlife Corridor, from Santa Ana River to Whittier Hills.

No original field studies. Interviews with previous researchers and compilation and analysis of existing field data.

See entries for Haas and Crooks (1999) and Case and Fisher (1998) below. A comprehensive GIS database of their results was made available for research and monitoring.

Conservation and restoration of numerous lands, and proper management of these lands, is essential to stave off further species losses and ecological collapse in the Puente and Chino Hills.

Puente-Chino “Missing Middle” Analysis
Table 1. Continued. Conservation Biology Institute 9 July 2005 Reference Target Species Major Focus Study Area Methods Relevant Results Recommendations Haas et al. 2002, Case and Fisher 1998 Reptiles and amphibians
Determine distribution and diversity of herpetofauna; identify management needs to maintain diversity.

Scattered locales across the PuenteChino Hills Wildlife Corridor, from Chino Hills State Park to Whittier Hills.

Field methods:Pitfall drift-fence arrays and snake traps. Statistical analyses: Several measures of species richness and diversity analyzed relative to landscape position.

Species richness and diversity were generally highest in the Chino Hills (22 species) and Whittier Hills (14 species), with lower levels in the narrower, more fragmented areas between (10-12 species). The number of sensitive species declined from seven in the Chino Hills to four in the Whittier Hills, and the western limit for some species lies somewhere between Chino Hills and Whittier Hills. Several species (e.g., coast horned lizard, western skink, red diamond rattlesnake) showed decreased population densities moving west through the corridor.

Maintain habitat linkages to maintain gene flow and reestablishment of populations if localized extinctions occur.

PCR 2002 General
wildlife, with focus on large mammals.

Assess onsite biological resources and wildlife movement corridors to understand constraints to development on the ShellAera property.

Shell-Aera property and immediate vicinity; representing the western half of the Missing Middle (between SR-57 and Harbor Blvd.).

Sign reconnaissance; unbaited track stations, camera stations, and scat surveys focused on expected corridors and bottlenecks, such as road crossings; analysis of roadkill records.

Documented use of Shell-Aera property by deer, bobcat, coyote, roadrunners, and other native wildlife. Greatest evidence of wildlife movement was concentrated from the southeast corner of the property (associated with Tonner Bridge) to the northwest corner (associated with Drainage 26 and an area of high roadkill on Harbor Blvd.). Documented primary and secondary movement corridors across the property.

N/A--This biological constraints analysis describes existing conditions on the property and does not present recommendations.

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Methods
This study synthesized and updated existing information on wildlife distribution and movements in the Puente-Chino Hills Wildlife Corridor (see Table 1) to serve as a “meta-analysis” of overall corridor function and of the role that each portion of the corridor plays in supporting native wildlife and wildlife movement. After analyzing existing conditions, I also considered how land-use changes in the Missing Middle could affect the continued persistence of wildlife populations throughout the corridor and in each portion of the corridor. The analytical process involved

1. Selecting a suite of target species for which there is sufficient local information to assess distribution and movements;

2. Defining geographic units of the corridor system and assessing their functions in supporting these target species;

3. Assessing the roads that segment the study area as potential barriers or filters to movement; and

4. Assessing how the current functionality of these segments could change with various development scenarios.

Reconnaissance
The analysis of existing literature was supplemented with reconnaissance surveys in the field as well as using satellite imagery, high-resolution aerial photographs, and digital photographs taken during flyovers by Melanie Schlotterbeck. In particular I used the Keyhole program (www.keyhole.com) to perform a “virtual reconnaissance” of the study area, including properties where physical access was not possible. Keyhole3
allows a user to zoom, pan, tilt, rotate, and
otherwise explore a three-dimensional digital model of the Earth’s surface covered with high resolution satellite imagery (2004-5 color images at 1-m resolution) and Geographic Information System (GIS) data that can be layered onto this imagery. This proved to be an ideal tool for “exploring” the terrain prior to the field visit, and while reviewing previous studies in the area, to determine how topography, vegetation, development, and other landscape features might influence target species movements. By zooming in, rotating, tilting, and moving along this virtual landscape, a wildlife biologist can readily see where steep terrain, road cuts, bridges, vegetation, housing developments, and other landscape features would tend to funnel movements by larger species across the study area. (For example, I predicted, based on Keyhole reconnaissance, that the stretch of Harbor Boulevard just south of Wellington Lane would be a deadly road crossing for large mammals, which was later confirmed by personal observations in the field and my literature review.)

3 Reduced-resolution screen captures of Keyhole imagery are used to illustrate landscape issues throughout this report.

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After extensive exploration of the study area using Keyhole, GIS, and high-resolution aerial imagery, I visited the study area on March 2, 2005. I drove all roads crossing the area, stopping to investigate road-crossing structures (bridges, culverts, etc.), walking sections of trails, and looking for wildlife and wildlife sign. I photographed key locations, roadkills, habitat conditions, and other pertinent scenes, and noted signs of wildlife on aerial photographs.

Because my fairly cursory field observations strongly reinforced the quantitative results of more intensive studies (see Table 1), they are not presented in detail, but are cited as supporting or supplemental evidence for the results and recommendations of these previous studies.

Target Species
It is important to clearly define what species and ecological processes are expected to benefit from a wildlife movement corridor (Rosenberg et al. 1997, Beier et al. in press). Target species were selected based on data availability (see Table 1) and how well they reflect overall corridor function or serve as indicators of habitat fragmentation and movement constraints. They include species that require large areas to survive, are most susceptible to extirpation by habitat fragmentation, are most susceptible to roadkill, or for which roads may serve as physical barriers. In addition, previous studies provide some more general measures of ecosystem health and corridor function, such as species richness for amphibians and reptiles (Haas et al. 2002) and avifauna (Cooper 2000).

Although it is tempting to think of one or a few larger mammal species as most obviously served by movement corridors, the ecological effects are far broader than any single species or set of species. Ultimately, the objective of securing and managing the Puente-Chino Hills Wildlife Corridor is more than ensuring that mountain lions can continue roaming the area (although that is certainly one objective)—it is ensuring that healthy ecological communities can continue to thrive and support the broadest possible range of native species.

Mountain Lion
The mountain lion or puma (Puma concolor) is the top carnivore in Southern California. It is a true “keystone” species whose presence helps maintain ecological balance by controlling populations of deer and other prey (Soulé and Terborgh 1999, Crooks and Soulé 1999).

Mountain lions require huge contiguous habitat blocks to persist, with individual lions roaming home ranges as large or larger than the entire Puente-Chino Hills study area. Only contiguous habitat areas large enough to support at least 20 individuals—about 2,000 sq. km in Southern California—are expected to support lion populations over even the short term (Beier 1993, Beier et al. in press). Due to demographic instability and inbreeding concerns, even populations meeting these criteria, such as the population of about 20 adult lions occupying the 2,070-sq.-km Santa Ana Mountains Range, must be connected to even larger populations for long-term persistence (Beier 1993).

Although the Puente-Chino Hills are too small (at about 163 sq. km) to support a population of mountain lions on their own, one to several lions live totally or partially within the hills as an Puente-Chino “Missing Middle” Analysis
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extension of the larger Santa Ana Mountains population (Beier 1993, Noss et al. 1997). The Coal Canyon wildlife underpass on Highway 91 was restored specifically to ensure the continued presence of these large predators in the Puente and Chino Hills, thus ensuring a more healthy and balanced ecosystem (Noss et al. 1997). Lions have been detected all the way to the westernmost portions of the corridor (Whittier Hills) in recent years (A. Henderson, A. Gullo, and C.

Schlotterbeck, personal communications).

Lions are very prone to roadkill. During Beier’s (1993, 1995) study of mountain lions in the Santa Ana Mountains, vehicles killed 33% of the population, including four lions killed at one road-crossing during a 2-year period. Thus, mountain lions are good focal species for conservation planning in the study area, due to their keystone status, large area requirements, dependence on intact corridors, and susceptibility to roadkill.

Bobcat
Bobcats (Lynx rufus) are excellent indicators of functional landscape connections at the scale of interest in the Puente-Chino Hills study area (Crooks 2002, Haas 2002, Tigas et al. 2002, Riley et al. 2003). In Southern California, bobcat home ranges average about 2 to 6 sq. km, and population densities average about 1.1 to 1.6 bobcats per sq. km (Riley et al. 2003, Lembeck 1978, Lyren 2001). The probability of bobcat occurrence in a habitat patch is directly related to both the size of the patch and its isolation from other patches (Crooks 2002), with patches as small as 10 sq. km highly likely to support a few individuals if they are close enough together (within 1 km or less) and adequately connected to allow inter-patch movement (Crooks 2002).

Using radio telemetry in the Santa Monica Mountains, Riley et al. (2003) found habitat blocks as small as 3.15 sq. km to support a few individuals, as long as movement was possible to larger, source population areas. Taking into account variation in habitat quality, Beier et al. (in press) concluded that contiguous habitat blocks of about 60 sq. km are necessary to support potential source populations of 20-25 adult bobcats over the short term in Southern California. Noss et al. (1997) estimated that a population of less than 50 bobcats inhabited the Puente and Chino Hills and less than 500 bobcats inhabited the Santa Ana Mountains. Haas (2002) found bobcats to be associated with wider portions of the Puente-Chino Hills, with lower densities in narrower segments. He concluded that bobcats used smaller segments primarily as “move-through” rather than “live-in” habitat.

Bobcats are behaviorally secretive and tend to avoid roads and other human disturbances, although they remain quite susceptible to roadkill. Bobcats are less likely to use road underpasses than coyotes, especially narrow underpasses or underpasses near residential areas, and so may be better indicators of high-quality road-crossing structures for wildlife.

Coyote
Coyotes (Canis latrans) are more adaptable, more abundant, and less averse to fragmentation than bobcats and mountain lions—and thus less dependent on high-quality landscape connections. Nevertheless, coyotes are important to maintaining ecological balance (Crooks and Puente-Chino “Missing Middle” Analysis
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Soulé 1999) and are good indicators of problem road-crossings, as many are killed on roads in the study area and elsewhere (Lyren 2001, Haas 2000, Robertson et al. 1995). Concentrations of coyote roadkills provide good indicators of potential crossing locations for other species, including bobcats, mountain lions, and mule deer. Noss et al. (1997) estimated a carrying capacity of roughly 60 adult coyotes for the Puente and Chino Hills and less than 500 in the Santa Ana Mountains.

Mule Deer
Mule deer (Odocoileus hemionus) are the primary prey of mountain lions and require relatively large habitat areas to support populations. Although they adapt to living in close proximity to humans, and are found in portions of the study area that are effected by fragmentation and development edges (Haas 2000), they are prone to roadkill and highly selective of road-crossing structures. In general, deer will use only the largest, most open types of structures (bridges or very open box culverts) within well-vegetated habitat areas to cross under (or over) roads (Haas 2000, Clevenger and Waltho 1999, Evink 2002). Noss et al. (1997) estimated that about 400 mule deer may inhabit the Puente and Chino Hills and about 4,000 may inhabit the Santa Ana Mountains.

Greater Roadrunner
Greater roadrunners (Geococcyx californianus) are associated with coastal scrub and open brush mosaics in coastal Southern California. They are highly susceptible to roadkill (Unitt 2004) and particularly sensitive to habitat fragmentation, rapidly disappearing from isolated habitat patches (Unitt 2004, Crooks et al. 2001, Soulé et al. 1988, Garrett and Dunn 1981). Soulé et al. (1988) and Crooks et al. (2001) identified the roadrunner as the most sensitive to habitat fragmentation of eight scrub-dwelling species they addressed in San Diego County. Crooks et al. (2001) found roadrunners persisting in only one of 34 canyons isolated by urbanization, and estimated that the roadrunner has a good chance of persisting only in patches 1.6 sq. km or larger. Based on more exhaustive surveys, Unitt (2004) concluded that this underestimates roadrunner sensitivity to isolation; he suggested that even 4.0-sq. km patches may be too small to sustain populations for long. As snakes and lizards are important prey, roadrunners may decline with reductions in reptile diversity and abundance.

Cooper (2000) reported that roadrunners are scattered in association with scrub habitats throughout the Puente-Chino Hills study area, with particular concentrations in the hills north of Brea and Yorba Linda (including significant portions of the Missing Middle). He estimated there were more than 50 breeding pairs (100 adult individuals) living in the Puente and Chino Hills.

Coast Horned Lizard
The coast horned lizard (Phrynosoma coronatum) was once common and widely distributed in coastal sage and chaparral habitats of Southern California, but has been extirpated from much of Puente-Chino “Missing Middle” Analysis
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its former range by habitat loss and fragmentation (Fisher et al. 2002). This species is highly impacted by edge effects, such as invasions by the nonnative Argentine ant, which eliminates the native harvester ants that comprise more than 95% of the horned lizard’s diet (Suarez et al. 2000). Argentine ants are closely associated with human-altered (especially irrigated) landscapes in Southern California, but can invade hundreds of meters into native scrub habitats; their adverse effects on native invertebrate populations ripple through the ecological community with devastating effects on biological diversity (Suarez et al. 1998). Thus, horned lizards serve as good indicators of relatively intact ecological webs and processes or, conversely, of the adverse effects of habitat fragmentation and edge effects on ecological communities (Fisher et al. 2002). They are also highly susceptible to roadkill and trampling. Case and Fisher (1998) and Haas et al. (2002) found coast horned lizards in the Chino Hills, as far west as the ridges between Carbon Canyon and Tonner Canyon (near the Olinda Landfill), but did not detect them at points farther west. Therefore, this species may already be extirpated, or likely will be soon, in corridor segments west of Highway 57 due to isolation of populations by roads and high mortality in remaining habitat areas.

Other Target Resources
The above target species certainly do not comprise a complete list of resources subject to loss due to habitat fragmentation and associated effects. They serve as indicators for a much more diverse community of organisms, and were chosen largely on this basis as well as the availability of distribution data in the study area. In addition to these species, I examined information on the diversity and abundance of reptiles and amphibians (from Case and Fisher 1998, Haas et al. 2002) and birds (Cooper 2000), and considered, at least qualitatively, the effects of habitat fragmentation on other species and ecological processes in the study area.

Defining Geographic Units, Barriers, and Filters
Although the entire study area serves as a wildlife movement corridor at a gross scale, it functions more like a peninsula of somewhat discrete habitat blocks segmented by roads and other discontinuities (Haas 2000, Haas and Crooks 1999, Schlotterbeck 2001, Robertson et al. 1995). The Puente-Chino Hills Wildlife Corridor was therefore subdivided into discrete geographic units based on habitat contiguity and intervening roads. Each unit, including the Santa Ana Mountains (the core area from which the corridor system projects) and the isolated terminal segment at the Whittier Narrows (Robertson et al. 1995), was given a geographic name to facilitate comparison (Map 2). Following Haas and Crooks (1999), the seven units between these two extremes (or between Highway 91 and Interstate 605) were also numbered 1 to 7, from east to west. These seven segments comprise the functional Puente-Chino Hills Wildlife Corridor system. They are convenient for comparing results across the various field studies and for assessing how each segment, and the habitat breaks between them, contribute to overall functionality of the corridor system. These segments are therefore useful tools for conservation planning.

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Map 2. Geographic units of the Puente-Chino Hills Wildlife Corridor.

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Initial Classification of Geographic Units
Each geographic unit was first classified by the primary role it appears to play in the overall functioning of the wildlife corridor system—as a biological core, subcore, patch, or isolate.

These functional categories, defined below, reflect the relative size and contiguity of the units and their ability to sustain populations or facilitate movements of target species, as supported by literature and results of previous wildlife studies here. These definitions are tailored to this particular study, based on well established conventions in reserve design (e.g., Noss 1987, Meffe and Carroll 1997, Soulé and Terborgh 1999), and modified slightly from concepts and definitions developed for the South Coast Missing Linkages project—a science-driven approach to conserving landscape connectivity throughout the South Coast ecosystem (Beier et al. in press). The most significant deviation from the definitions of Beier et al. (in press) is the inclusion of an intermediate-sized “subcore” class (which corresponds to a “patch” in Beier et al. in press).4

• Core — A core area must be large enough (> 2,000 sq. km) to sustain populations of most or all target species without the need for frequent immigration from other areas, and should have relatively high biological diversity and a low proportion of edge. Core areas support source populations of target species, which may contribute individuals to other, less substantial, blocks of habitat. Basically, a core should be large enough to support a population (at least over the short term) of the most wide-ranging and area-dependent target species, which in this case is the mountain lion. • Subcore — Subcores are contiguous blocks of habitat at least 60 sq. km, but less than 2,000 sq. km (corresponding to a “patch” as defined by Beier et al. in press). Subcores are too small to sustain a population of mountain lions in isolation, but large enough to support a population of bobcats with at least occasional dispersal. Subcores may support one or a few individual mountain lions, or at least provide significant “live-in” habitat as part of one or more lion home ranges. Subcores are more edge-effected than cores and may sustain lower overall species diversity, but can nevertheless represent significant source populations for numerous other target species, such as roadrunners, coyotes, and horned lizards.
• Patch — Patches, at less than 60 sq. km, are smaller and more edge-effected than subcores and are expected to support overall lower numbers and diversity of species. In isolation, patches may be too small to support a population of bobcats, and perhaps other target species having intermediate area requirements, although they could support a small number of such species or at least represent live-in or move-through habitat for individuals of such species. Although they may support populations of less area-

4 Concepts like “core” and “corridor” are species- and scale-dependent, such that what might be considered a movement corridor for one species (e.g., mountain lion) can be core “live-in” habitat for other species (e.g., lizards, songbirds, or rodents). This entire study area is widely recognized as a “wildlife corridor,” even though numerous on-the-ground travel routes, population concentrations, etc., can exist within this overall corridor system at finer resolution.

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dependent target species, patches may serve mainly as dispersal stepping stones (or “move-through” habitat) for individuals of larger species (like mountain lions) moving between larger geographic units.
• Isolate — An isolate is any patch that is separated from another geographic unit by barriers to movement for target species. For example, the Whittier Narrows are separated from the Whittier Hills by Interstate 605, other significant roads, and commercial development, and are considered functionally isolated from the corridor for nearly all reptiles, amphibians, and mammals (Haas and Crooks 1999, Haas et al. 2000, Robertson et al. 1995, personal observations).

Note that these initial landscape categories were defined based primarily on the needs of the most area-dependent target species (mountain lion and bobcat). However, such concepts as “core” and “patch” can also be defined separately for each target species, based on their own requirements. Thus, a patch of habitat too small to support mountain lions could represent a “core” population area for less area-dependent species, like the roadrunner or horned lizard.

Such species-specific issues were treated in more detail in later analytical steps.

Classifying Barriers and Filters to Movement
Roads and other discontinuities in habitat were also classified based on their relative effects on movements and population distributions of species, as follows:
• Barriers and Near Barriers — Roads or other discontinuities between geographic units that are never (for barriers) or rarely (for near barriers) crossed by target species. Barriers effectively isolate target species populations on adjacent habitat units from one another, while near barriers may separate subpopulations into a “metapopulation” system, with individuals occasionally dispersing between subpopulations in different units. For wideranging species like bobcats or mountain lions, barriers or near barriers may define one boundary of a home range, as individuals recognize it as the edge of available habitat.

Major freeways and associated physical features (e.g., embankments, drainage improvements, retaining walls, lane dividers, fences, wide areas devoid of vegetation) create impassible barriers for nearly all ground-dwelling species, unless sufficient crossing structures (e.g., bridges, culverts, vegetated over-crossings) facilitate movements (Beier et al. in press, Evink 2002, Haas 2002, Lyren 2001). For example, the concentration of roads and commercial developments associated with Interstate 605, separating Whittier Hills from Whittier Narrows, represents a barrier for most or all target species. Near barriers are similar, but they may have one or more crossing structures that can be used by at least some target species; or target species may occasionally cross atgrade, on the road surface (perhaps at high risk of roadkill). Highway 57 and Harbor Boulevard are examples of near barriers in the study area. Both have high traffic volumes and physical characteristics that discourage crossings, except at one excellent bridge crossing at Tonner Canyon (for Highway 57) and one stretch where wildlife cross Harbor Boulevard at-grade—albeit with frequent roadkill.

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• Filter (Permeable and Highly Permeable) — Filters are discontinuities in habitat connectivity that are readily to moderately crossable by most but not all target species.

For example, two-lane paved roads with low traffic volumes and little associated development are readily crossed by larger mammals (although there may be occasional roadkill); but other species, like horned lizards, may be reluctant to cross or may suffer high roadkill. Thus, such roads serve to “filter” some species out of the community of wildlife crossing between adjoining habitat units. Several permeable to highly permeable roads cross the study area, such as Turnbull Canyon Road through the Whittier Hills (between Segments 6 and 7). The larger mammals, roadrunners, and some reptiles probably cross this road at-grade with little hesitation, and individual home ranges may straddle it. However, some smaller or more sedentary species may have their populations segmented by this road into subpopulations, with only occasional cross-road dispersal.

Analyses — Assessing Existing and Future Functionality
For each target species, I followed the following analytical steps:

1. I assigned each of the nine geographic segments to one of the functional categories (core, subcore, patch) as if each functioned independently of the others (i.e., as if roads separating the units acted as barriers or near barriers to dispersal). This initial categorization was based exclusively on unit size. For example, any unit less than 60 sq. km would be considered a patch if it functioned independently of other units in supporting a target species.

2. I assessed each road separating the units to determine whether it acted as a barrier (or near barrier) or filter (permeable to highly permeable). If a road was not considered a barrier/near barrier for a target species, and the two units it separated appeared to function as one larger unit for that species, the area of the two units was summed and the function of the new composite unit was reassessed. For example, if the composite unit exceeded 60 sq. km, it was considered to function as a subcore rather than two separate patches.

3. Based on this revised, species-specific functionality assessment, I assigned each newly defined unit (or composite unit) a function relative to supporting individuals or populations of each target species based on unit size, habitat composition, and other factors gleaned from the literature and field reconnaissance. These species-specific functions were defined as follows:
• Population — capable of supporting a breeding population of at least 20 adults and potentially serving as a source of individuals that disperse into other units. • Subpopulation — capable of supporting at least two but less than 20 breeding individuals. Not likely to be a reliable source population, but may exchange individuals with other areas within a larger metapopulation (a set of partially isolated Puente-Chino “Missing Middle” Analysis
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populations linked by occasional dispersal) and may provide individuals to recolonize habitat patches in case of local extirpation.
• Home Range Part — incapable of supporting at least two breeding individuals on its own, but may provide live-in habitat (e.g., foraging or resting cover) and form a part of one or more individuals’ home range(s).
• Move-through — not contributing significant live-in habitat for a species as part of a functional home range, but capable of accommodating movements between more substantial units within a home range, or potentially used for dispersal between other habitat units.

4. This classification system was used to assess likely effects of future scenarios on wildlife populations or movements, such as (a) adding new roads or development that would introduce new barriers or reduce the size of a functional unit, or (b) adding or improving wildlife crossing structures that would allow two independent units to serve as one larger one.

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Results
Functionality of Geographic Units
Table 2 summarizes characteristics of the geographic units, including their size, vegetation composition, known or inferred presence/absence of target species, initial functional classification (core, subcore, patch), and reserve status (conserved/unconserved). Only the Santa Ana Mountains unit met the definition of a core area (larger than 2,000 sq. km and capable of supporting a mountain lion population). The Chino Hills between Highways 91 and 142 met the definition of a subcore (60-2,000 sq. km and capable of supporting a population of bobcats). Six other segments of the Puente-Chino Hills Wildlife Corridor met the definition of patch, but with great variation in their capacity to support wildlife and wildlife movements. The disjunct Whittier Narrows met the definition of an isolate.

Table 3 summarizes pertinent characteristics of the major roads dividing these units, with a focus on their role as barriers or filters to wildlife movement. Following below is a more detailed, unit-by-unit review of the information, concerning how each unit appears to function in supporting wildlife populations and movements, considering the effects of intervening roads and other factors. This review starts with the Santa Ana Mountains Core Area, then describes the seven segments of the functional Puente-Chino Hills Wildlife Corridor, and ends with the isolated Whittier Narrows.

Santa Ana Mountains (Core)
At about 2,070 sq. km, wildlands in the Santa Ana Mountains comprise the only true core in the study area. They support a high diversity of wildlife in a relatively intact and healthy representation of Southern California’s South Coast ecosystem (Spencer et al. 2001), including substantial populations of all the target species. Noss et al. (1997) estimated populations of breeding adults in the Santa Ana Mountains at about 4,000 mule deer, 15-20 mountain lions, up to 500 bobcats, and more than 500 coyotes. These populations are large enough to persist, at least in the short term, within the Santa Anas without immigration from other habitat areas— although at least the mountain lion needs occasional immigration from adjacent mountain ranges to persist in the long term (Noss et al. 1997, Beier 1993). Of course, all species and ecosystem functions benefit from connectivity to other wildlands. The breeding population of about 15-20 mountain lions serves as a source of lions moving into the Puente-Chino Hills via the Coal Canyon Underpass (Beier 1995, Noss et al. 1997).

The Santa Ana core area is separated from the Chino Hills by busy Highway 91 and associated developments. However, the Coal Canyon Wildlife Underpass was restored specifically to mitigate this strong barrier to movements and appears to be functional (Figure 2).

Puente-Chino “Missing Middle” Analysis
Conservation Biology Institute 21 July 2005 Table 2. Characteristics of geographic units comprising the Puente-Chino Hills Wildlife Corridor (from east to west).

Segments of the Functional Puente-Chino Hills Wildlife Corridor Santa Ana
Mountains Chino
CarbonTonner Shell-Aera Powder- Schabarum San Miguel E. Whittier W. Whittier Whittier Narrows Segment Number N/A 1 2 3 4 5 6 7 N/A Size (sq. km.) ~2,070 85.6 44.3 13.3 5.7 1.5 5.2 7.1 ~4.5 Vegetation Mosaic Shrubland 51.3% 51.9% 45.2% 48.9% 57.1% 43.4% 67.0% Grassland 36.5% 29.4% 37.7% 21.0% 31.8% 36.1% 17.1% Woodland 12.1% 18.7% 17.2% 30.1% 11.4% 20.4% 15.9% Wetland N/A

0.1% 0.1% 0.0% 0.0% 0.0% 0.0% 0.0%
N/A
Spp. Presence/Absence* Mountain lion P P P P? P? P? P P A? Bobcat P P P P P P P P A? Coyote P P P P P P P P P? Mule deer P P P P P P P P ? Roadrunner P P P P P? P? P P ? Coast horned lizard P P P A? A? A? A? A? A? Biological Function core subcore large patch patch patch small patch patch patch isolate Reserve Status substantially conserved
substantially
conserved
Carbon Cyn
partly
conserved,
Tonner Cyn
unprotected &
threatened
unprotected
& threatened
partly
conserved,
partly
threatened
partly
conserved,
partly
threatened
substantially
conserved
substantially
conserved
substantially
conserved
*See Table 1 for supporting literature. P = confirmed present; A = likely absent; ? = presence or absence inferred by indirect evidence and geographic context, but no confirmatory data found.

Puente-Chino “Missing Middle” Analysis
Conservation Biology Institute 22 July 2005 Table 3. Characteristics of roads crossing the Puente-Chino Hills Wildlife Corridor. Road Geographic Units Separated Critical Crossing Structures* Characteristics Effect on Movements SR 91 Santa Ana/Chino Coal Canyon Wildlife Underpass
Major, 6-lane freeway with heavy traffic and significant physical barriers to wildlife.

Barrier, except for Coal Canyon Underpass
Carbon Canyon Rd. (SR 142)
Chino/Carbon-Tonner Square box culvert near
Chino State Park entrance.

Busy 2-lane highway through mostly wild open space. Moderate-high coyote roadkill. Few physical barriers.

Permeable filter, with some roadkill (esp. coyote). Mix of at-grade crossings and culverts, at least one used by bobcat.

SR 57 Carbon-Tonner/ShellAera Tonner Canyon Bridge Major 6-lane freeway with heavy traffic and significant physical barriers to wildlife. Barrier except for Tonner Canyon Bridge, with documented use by deer, bobcat, and coyote.

Harbor Blvd. Shell-Aera/PowderSchabarum Harbor Blvd. Wildlife Tunnel (proposed) Major 4-lane arterial with heavy traffic and significant barriers to wildlife. High roadkill. Barrier, except for occasional at-grade crossing, with very high roadkill. Hacienda Blvd. Powder-Schabarum/San Miguel
none (except a littleused equestrian tunnel that could be improved) Busy 2-lane road with steep slopes and cut banks, but several at-grade crossing areas.

Filter, with moderate roadkill risk.

Colima Rd. San Miguel/East Whittier Colima Service Tunnel Busy 4-lane road with physical barriers, including fences that may help funnel wildlife to undercrossing.

Filter, with relatively low roadkill due to fences and a well-used undercrossing with known use by deer, bobcat, and coyote.

Turnbull Canyon Rd.

East Whittier/West Whittier
none Winding, 2-lane road with light traffic
through wild habitat.

Highly permeable filter, with at-grade crossings in wild open space.

Interstate 15 & Workman Rd.

West Whittier/Whittier Narrows
none Major 6-lane freeway with heavy traffic, plus
other major and minor roads, commercial development, and other physical barriers to wildlife.

Barrier to essentially all ground-dwelling species.
*Includes only those structures used by diverse target species and especially larger mammals. Numerous smaller culverts that may serve some target species also occur, as do some larger equestrian tunnels that are in landscape positions not favoring use by target species. See Haas (2000) and Robertson et al. (1995) for a more comprehensive review of crossing structures in the study area.

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undoubtedly reflect the larger size of Segment 1 (and adjoining Segment 2) compared with other segments, its proximity to the Santa Ana Mountains Core, and the increasing number of barriers and filters encountered moving west from this source area through the corridor. Similar patterns in diversity, abundance, and evenness measures would be expected for other taxa (e.g., birds, small mammals, insects, plants) if comparable data were available to document them.

Segment 1 is largely conserved already as Chino Hills State Park, although efforts continue to increase the size and buffering of this important reserve area. It is separated from Segment 2 by Carbon Canyon Road (Highway 142). This busy 2-lane road suffers some roadkill, especially coyote (Robertson et al. 1995), but is generally quite permeable to target species due to extensive, naturally vegetated land on both sides, lack of development over much of its length, and availability of several undercrossings. The most significant undercrossing is a 1.4-m (4.5-ft) high square box culvert used by bobcats and other target species (Robertson et al. 1995). This road is therefore classed as a permeable filter, allowing Segments 1 and 2 to function as one larger subcore for most species and ecological processes. Notably, Haas et al. (2002) and Case and Fisher (1998) recorded coast horned lizards on both sides of Carbon Canyon Road, but not farther west along the corridor.5
Corridor Segment 2—Carbon-Tonner
This large (44.3 sq. km) patch appears to function more as an extension of the Chino Hills subcore, being separated only by permeable Carbon Canyon Road (see previous). It is biologically diverse and supports all target species, including the westernmost observations of horned lizards by Haas et al. (2002) and Case and Fisher (1998). The southern portion of Segment 2 (including lower Carbon and Tonner Canyons and associated ridges) has been identified as a conservation priority for birds due to its support of several regionally rare or declining species, including greater roadrunners, loggerhead shrike, cactus wren, California gnatcatcher, grasshopper sparrow, and sage sparrow, among others (Cooper 2000). The northern portion of the segment (upper Tonner Canyon) is also rated as a conservation priority for birds, including golden eagle, burrowing owl, northern harrier, cactus wren, tricolored blackbird, and grasshopper sparrow, among others (Cooper 2000). Tonner Canyon also supports significant California walnut woodlands.

The eastern half of Segment 2 contains the western slopes and ridges of the Carbon Canyon landscape and is partially conserved as part of Chino Hills State Park and the Firestone Scout Reservation. The western half of this segment, containing most of Tonner Canyon, is unconserved and threatened by several proposed developments. Tonner Canyon is almost entirely owned by the City of Industry, which proposes a new road along the east side of Tonner Canyon (Map 2) and new water reservoirs within the canyon. This threatened half of the segment comprises the eastern portion of the Missing Middle.

5 During my literature review, I found no recent confirmed records for coast horned lizards farther west than a ridge between Carbon and Tonner Canyons near Olinda Landfill (Haas et al. 2002). However, one table in a draft report (LSA 2005) listed the species as “observed” in the Whittier Hills, although another table in the same reference indicated the horned lizard as potentially present but not observed there.

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used crossing structures. An existing equestrian tunnel, that is infrequently used by target species, could be improved with fencing and revegetation (Haas 2000 and personal observations). Hacienda Boulevard has several at-grade crossing concentrations and trails (Haas 2000, Robertson et al. 1995, personal observations), which are probably associated with moderate roadkill. I rated this as a permeable filter, as it is crossable by most target species; however, it may act as a strong filter due to these and other constraints, and it represents a bottleneck to movement in need of improvement (Haas 2000).

Corridor Segment 5—San Miguel
This is the smallest (1.5 sq. km) segment of the entire corridor system. Along with the narrow constriction in the west end of Segment 4, this segment represents the narrowest habitat constriction along the wildlife corridor system (0.5 to 1.0 km wide). It is also perhaps the most disturbed by humans and their pets, particularly on northern slopes (Haas 2000, Robertson et al. 1995). Haas recorded low use by target species (no bobcat use) on the northern portions of this segment, along the Skyline Trail, but high levels of cats, dogs, striped skunks, and raccoons. The abundance of these mesopredators that are adapted to human environments often reflects low presence of coyotes and other large predators, which suppress these species when present (Crooks and Soulé 1999), as well as higher human influences and edge effects. Haas (2000) recorded bobcat activity in the southern portion of the segment, in association with less disturbed areas of San Miguel Canyon and near Skyline Drive. He noted that the transects with the greatest bobcat activity were also those with the lowest dog activity. Haas surmised (as did Robertson et al. 1995) that large mammals travel along Skyline Drive and descend into San Miguel Canyon towards the Colima Service Tunnel (discussed below). Low density housing in this segment, especially near Hacienda Boulevard, may reduce habitat quality for target species, but does not present barriers to movement (Haas 2000, Robertson et al. 1995). For some target species, Segment 5 may function primarily as move-through habitat, although a few coyotes and bobcats probably forage in San Miguel Canyon.

Segments 5 and 6 are divided by Colima Road, a fairly busy 4-lane road winding through a mix of open space and scattered housing. Although flanked by steep slopes, some fences, and other movement impediments, there are several at-grade crossing areas, which are associated with high coyote roadkill (Haas 2000, Robertson et al. 1995). One good under-crossing structure exists at a service tunnel near the southern edge of the habitat area (Colima Service Tunnel). Bobcats, coyotes, and deer use this tunnel (Robertson et al. 1995, Haas 2000, Haas and Turschak 2002), and they continued using it even after a dramatic increase in recreational uses of the tunnel and vicinity by humans and dogs during 2001-2002 (Haas and Turschak 2002). Most wildlife species use the tunnel between sunset and sunrise, whereas human and dog use occurs almost exclusively during daylight (Haas and Turschak 2002). Conserving and improving this tunnel for continued wildlife use, especially at night, is a conservation priority.

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Corridor Segments 6 and 7—East Whittier and West Whittier The wildlife corridor widens again in the Whittier Hills from the narrow and constrained Segments 4 and 5. Segments 6 and 7 are separated by Turnbull Canyon Road, which appears to be the most permeable road analyzed in the study area. It is a narrow, 2-lane road with relatively light traffic, winding through fairly undisturbed wildlands. Haas (2000) recorded no roadkills here and did not consider Turnbull Canyon Road a barrier or major hazard to mammals.

Likewise, Robertson et al. (1995) did not consider Turnbull Canyon Road a significant impediment to movement, which corresponds with my field observations. Consequently, Segments 6 and 7 are discussed here together as one continuous geographic unit (Whittier Hills).

The Whittier Hills support significant biological values despite their location at the terminus of the range of connected wildlands, far from the Santa Ana Mountains Core. This area had the highest levels of deer and bobcat activity recorded by Haas (2000), and higher species richness of reptiles and amphibians than narrower segments farther east (Haas et al. 2002). Mountain lion presence has recently been confirmed in the area by several lion-predated goats and deer, and at least one likely lion scat (Haas 2000; A. Henderson, C. Schlotterbeck, and A. Gullo, personal communications).

However, monitoring results also show that the Whittier Hills have lost some species and may be close to losing more due to their distance from core areas and numerous intervening barriers and filters to movement. For example, despite the relatively high total number of reptile and amphibian species they recorded here, Haas et al. (2002) also found the Whittier Hills to have the lowest overall evenness in the study area (Haas et al. 2002). This evenness finding means that the local herpetofauna consists of a few abundant species plus many less abundant species, in contrast to the Chino Hills, where high evenness indicated healthy populations of most species.

Those species detected in low numbers in the Whittier Hills may represent remnants of dwindling populations, possibly on their way to extirpation with little hope of being “rescued” by new colonists from other areas (Brown and Kodric-Brown 1977) due to the great distances and numerous barriers involved. Moreover, the Whittier Hills support fewer sensitive species of reptiles and amphibians than the Chino Hills, as various species drop out in an apparent east-west gradient from the Chino Hills through the wildlife corridor to the Whittier Hills (Case and Fisher 1998, Haas et al. 2002).

The Whittier Hills are separated from the Whittier Narrows by an array of formidable barriers, including Workman Road, Interstate 605, and a wide, unbroken surface of buildings and pavement. Together, these create a near total barrier to movement for all target species.

Whittier Narrows (Isolate)
Because it is functionally isolated from the Puente-Chino Hills Wildlife Corridor, I did not investigate this area in detail. Although this matrix of wetland and disturbed upland habitats probably supports some coyotes (a semi-isolated subpopulation?), it is unlikely to support other target species in perpetuity.

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Summary of Overall Corridor Function
In general, the Puente-Chino Hills Wildlife Corridor appears to be functional for at least larger mammals and birds, although tenuously so in the Missing Middle (due to several barrier roads and near barrier roads) and across smaller Segments 4 and 5 just west of the Missing Middle (due to their small size, strong edge effects, and high human and dog activity). Essentially all roads in the study area are considered barriers or at least strong filters to movements by many reptiles, amphibians, and small mammals, although most birds and larger mammals currently can move between all segments either at-grade (with mortality risks) or via critical crossing structures. Despite constraints in many locations along the corridor, target species are confirmed or highly likely to occur in all seven corridor segments, except for the coast horned lizard, which may already be absent, or will disappear in the future, west of Highway 57.

Mountain lions are capable of traversing the length of the corridor, albeit at some risk of roadkill, and one or more lions still hunt as far west as the Whittier Hills. Most other target species probably persist over the length of the corridor as metapopulations, with subpopulations segregated among geographic units by the presence of barrier or near barrier roads. These subpopulations may be linked demographically and genetically by occasional dispersal, or by within-home range movements of some individuals, depending on each species’ ability to navigate roads and crossing structures. For example, bobcats apparently have small subpopulations living in the Whittier Hills and within Segment 3 (Shell-Aera), and a larger source population living within the Chino Hills (Segments 1 and 2). Some individual bobcats probably have home ranges completely or partially within smaller segments (e.g., 4 and 5) between these more substantial habitat areas; or they occasionally move through the smaller segments, between larger ones, and thus keep the overall metapopulation interconnected demographically and genetically. This metapopulation persistence depends on both occasional cross-road movements (i.e., functional road-crossings) and sufficient patch size and habitat quality to sustain small subpopulations within segments.

Haas et al. (2002) described a gradient of declining diversity and evenness of reptile and amphibian species, moving west from the Chino Hills. This must be attributed to higher mortality and edge effects in the more fragmented portions of the study area, exacerbated by the greater distance and increasing number of barriers and filters that must be crossed as one moves farther west from source populations. This pattern of decreasing biological diversity in the western portions of the corridor is likely to be mirrored by other taxa that respond similarly to distance and barrier effects, such as small mammals. In terms of metapopulation dynamics, if a local population or subpopulation dwindles or disappears from one segment (e.g., Whittier Hills), it is less likely to be “rescued” by colonists from other segments (e.g., Chino Hills) the farther away it is from the source population and the greater the number of intervening barriers and filters. Hence, the farther west a segment lies, the greater the likelihood of local population declines or extirpations, at least for less mobile species (Haas et al. 2002).

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Table 4 summarizes the conclusions from the preceding review of geographic units and roads and presents a conceptual model of how each geographic unit (or composites of adjoining units lacking barriers) appears to function in supporting populations of target species within this segregated landscape. This table integrates diverse information, including published estimates of home ranges and densities of target species in Southern California, results of the monitoring studies summarized in Table 1, variation in habitat quality and mortality factors throughout the study area, and professional judgment. The carrying capacity estimates (in parentheses for some species) are rough approximations only, intended as order-of-magnitude estimates of the capacity of each geographic unit to support populations or subpopulations of target species, or to function as part of one or more home ranges, or to function as pass-through habitat between other units.

Where adjoining segments are considered to function as one unit for a particular target species (e.g., if individuals readily cross roads and populations are not considered segmented by them), the area of those segments is summed. Thus, Segments 1 and 2 are combined to form new Segment 1/2 (Chino-Tonner), because Carbon Canyon Road is quite permeable for most species.

Likewise, Segments 6 and 7 (the Whittier Hills) appear to serve as one contiguous geographic unit for nearly all target species, except the horned lizard, which is likely absent.

Vertical lines separating adjacent segments in Table 4 represent roads considered to segment populations for a given species. However, note that even where barrier roads do not prevent movement between adjoining segments, those segments may be treated separately in the table’s classification of segment function for a target species. For example, although the roads bounding Segment 5 are not considered mountain lion barriers, Segment 5 is rated separately as “passthrough habitat” for lions (due to small size and edge constraints), whereas Segment 4 and combined Segments 6/7 are considered foraging habitat and therefore parts of a functional home range for one or two lions that pass through Segment 5 to reach them. Similarly, although Colima Road is not a strong barrier to movement for bobcats, coyotes, or deer, narrow and edgeeffected Segments 4 and 5 likely support, at most, small subpopulations (a few resident individuals) or portions of a few individual home ranges for these species, whereas the larger and more contiguous Whittier Hills unit can support more robust and sustainable subpopulations.

By reading across the rows of Table 4 for any species, one can envision how the presence of species is maintained throughout the corridor via individual movements and metapopulation dynamics, with each segment (or combination of segments) serving as stepping stones along the way (either for an individual of a wide-ranging species like mountain lion—which may traverse the entire corridor—or over several generations for smaller species, whose individuals may move over only one or a few segments in a lifetime). For example, the only source population for mountain lions is the Santa Ana Mountains Core. The one to three resident lions that use the combined Chino-Tonner unit would not be there without this core population or the Coal Canyon Wildlife Underpass (Beier 1993, Noss et al. 1997, Haas 2000). One or more of these resident lions at least occasionally use Segment 3 (Shell-Aera) as foraging or pass-through habitat as a portion of their home range (made possible by the Tonner Bridge between Segments 2 and 3).

From there, one or more lions occasionally forage in or move through Powder Canyon (Segment 4) and San Miguel Canyon (Segment 5) to forage in the Whittier Hills (combined Segments 6/7).

Puente-Chino “Missing Middle” Analysis
Conservation Biology Institute 33 July 2005 Table 4. Functional classification of geographic units for supporting target species populations and movements, considering effects of inter-unit barriers and filters, road-crossing structures, habitat quality, and other factors. Vertical lines indicate presence of barriers or near barriers between units for that species (names supplied for major roads). Classifications spanning multiple unit columns indicate those units are assumed to function as one for that species, using the summed size of units. Carrying capacity (numbers in parentheses) are crude estimates only, based on results of monitoring studies (see Table 1), published home range sizes and densities, habitat mosaics in each segment, and professional judgment. They are intended as order-of-magnitude estimates for the purpose of assigning functional classes, and not as precise population estimates.

Segments of the Functional Puente-Chino Hills Wildlife Corridor 1/2–Chino-Tonner 6/7–Whittier Hills
Santa Ana Mtns
Core Area 1-Chino
2-CarbonTonner 3-Shell-Aera 4-Powder- Schabarum 5-San Miguel 6-E. Whittier 7-W. Whittier Whittier
Narrows
(Isolate)
Unit Size (sq. km) 85.6 44.3 5.7 1.5 5.2 7.1 Summed Size ~2,070
129.9 13.3 7.2 12.3
~4.5
Target Species Mountain lion Pop (15-20) Subpop (1-3) HR Part (1-2) HR Part (1-2) Pass-thru HR Part (1-2) Absent Bobcat Pop (100-400) Pop (20-50) Subpop (2-10) Subpop/HR Part (2-5) Subpop (5-15) Absent? Coyote Pop (200-500) Pop (20-50) Subpop (5-12) Subpop/HR Part (2-7) Subpop (15-25) Subpop? Mule deer Pop (2,000-4,000) Pop (100-300) Subpop (10-25?) Subpop/HR Part (5-15) Subpop (15-30) Absent? Roadrunner Pop (hundreds) Pop (20-100) Subpop (?) Subpop (?) HR Part (?) Pop(?) Absent? Coast horned lizard Pop (thousands) Pop (hundreds?) Pop (hundreds?) Absent? Absent? Absent? Absent? Absent? Absent? Pop = capable of supporting a breeding population of >20 individuals and potentially serving as a source population via dispersal to other segments.

Subpop = capable of supporting 2-19 individuals as part of a metapopulation connected by at least occasional dispersal between other segments.

HR Part = could comprise part of one or more individual home ranges in concert with adjoining areas, but by itself is unlikely to support a breeding pair. Pass-thru = used for movement between adjoining units, but unlikely to support individual life requisites (foraging, breeding, etc.) or a home range.

SR 57
Harbor Blvd
Colima Rd
SR 91
I- 605
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If any of the critical road crossings becomes non-functional, lions would no longer use more westerly segments, because no segments are capable of supporting a population of lions in isolation (other than the Santa Ana Mountains Core). Moreover, if any segment is reduced in size or quality to become only move-through habitat (rather than live-in habitat), the probability of lions using this unit, or any units lying further west, would drop considerably. Hence, maintaining lions in the Whittier Hills ecosystem depends not only on maintaining the possibility of unimpeded movement by individuals along the corridor, but also on maintaining substantial live-in habitat along the way.

Similarly, subpopulations in the Whittier Hills of bobcats, mule deer, roadrunners, and, to a lesser extent, coyotes exist in part due to other population or subpopulation segments (i.e., source habitats) along the corridor. Thus, the substantial habitat blocks in Segments 2 and 3 are important to continued presence of target species many kilometers away in the Whittier Hills.

Substantial reduction in the carrying capacity of any one segment increases the probability of species losses in other segments. Thus, for example, the large area of Segment 3 (Shell-Aera) is a major potential contributor to the continued presence of bobcats, mule deer, mountain lions, roadrunners, and many other species in the Whittier Hills, especially if habitat quality is increased and road crossings are improved.

To summarize, the ability of westerly segments of the corridor to support species depends both on (1) the potential for individual movement between each set of adjoining segments (a function of roads and road crossings), and (2) having sufficient live-in habitat along the way to support populations or subpopulations that contribute dispersing individuals. The greater the distance from or between source populations, the lower the probability of a habitat patch or group of patches to continue supporting that species. If the distance between occupied segments becomes too great, or if barriers prevent inter-segment movement, local extinctions are inevitable in the isolated segments. Thus, any reduction in the capacity of segments to support populations or subpopulations increases the probability of local extinctions in that segment, as well as in all other “downstream” segments to the west.

Importance of the Missing Middle to Corridor Function
This understanding of overall corridor function highlights the importance of the Missing Middle as a part of larger home ranges for more area-dependent species and for maintaining species use of segments farther west. Although there has been much attention to maintaining or improving road-crossing structures and avoiding new impediments to movement, there should be equal attention to maintaining functional habitat blocks, capable of supporting source populations of target species, within the Missing Middle. Currently, the eastern half of the Missing Middle (Tonner Canyon) serves as an extension of the large Chino-Tonner subcore, contributing dispersing individuals of target species to other segments. Likewise, Segment 3 (Shell-Aera), although somewhat smaller and degraded by grazing, undoubtedly supports significant numbers of target species that disperse (at some risk) across Harbor Boulevard into Powder Canyon and beyond.

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Although this conceptual plan appears to show approximately half the property as open space, it is clear that this open space represents far less than 50% of the property’s biological value, due to severe fragmentation and edge effects, disruption of movements, and elimination of live-in habitat. Much of the open space would be totally isolated between bubbles of development and roads, such as the open space bubble on the west side of Highway 57. This and other open space patches would be completely isolated from other habitat areas, removing their capacity to support target species and other native wildlife. Moreover, the narrow and highly convoluted bits of open space depicted in this plan would suffer severe edge effects, greatly reducing the area’s ability to support wildlife and ecological processes. As just one example, Argentine ants routinely invade several hundred meters from suburban edges into native scrub habitats, and even farther in moist drainages and canyons (Suarez et al. 1998). The open space bubbles are all less then 1 km across—much less in many places. Consequently, most if not all of the open space depicted in Figure 5 will be invaded by Argentine ants, which eliminate numerous native arthropods, plants, and vertebrates (such as the horned lizard) in a process of ecological collapse already well-documented in Southern California ecosystems (Suarez et al. 1998). In conclusion, only a minor fraction of remaining habitat will remain biologically useful in this proposed development area, and even that would be highly degraded relative to existing conditions.

The conceptual plan appears to be sensitive to wildlife movement needs in its depiction of a continuous “Wildlife Corridor” across the property, from Tonner Bridge through Drainage 26, to the location of the new wildlife tunnel being constructed under Harbor Boulevard. However, this characterization, apparently based on the primary movement corridor across the property as mapped by PCR (2002), is simplistic and biologically misleading. As concluded in the above review of corridor functions, long, narrow gauntlets of “move-through” habitat will not ensure continued functionality of the corridor system, which depends heavily on retaining the large blocks of live-in habitat in the Missing Middle. The mapped open-space corridor is about 4.5 km long and averages less than 500 m wide, which is insufficient to provide reliable live-in habitat for mountain lions and bobcats, for example. This is especially true considering that Segments 4 and 5 are also rather narrow and edge-effected, with marginal capacity to support foraging mountain lions or a subpopulation of bobcats. The overall result would be about 13 km of mostly linear, edge-effected, move-through habitat for these species, from live-in habitat east of Highway 57 to the next reliable foraging or subpopulation area in the Whittier Hills. The likelihood of continued movements by at least bobcats and mountain lions between Tonner Canyon and Whittier Hills would therefore drop dramatically with this development scenario.

In conclusion, this proposed housing development would seriously degrade the ability of Segment 3, and all segments farther west, to continue supporting target species, including mountain lion and bobcat. This would have cascading effects on flora and fauna in segments farther west, especially when considered in context with the relatively small and edge-effected Segments 4 and 5 it connects to on the west. Mule deer populations may, at least temporarily, increase in westerly segments like the Whittier Hills, due to removal of mountain lions from the system. In the short term, this may result in increased car-deer collisions on local roads; but in the long term, even deer are likely to disappear from all segments west of Highway 57 due to isolation of this relatively small population.

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area (northeast of the Firestone Scout Reservation), although supporting some target species and other wildlife, is mostly open grassland and somewhat degraded in habitat quality. Although a reservoir confined to this upper area would incrementally reduce the size of this segment and its capacity to support target species populations, it is far enough removed from the primary corridor connection across the Missing Middle that it would have less effect on overall corridor function than other developments I considered. However, any development (for reservoirs or other purposes) in middle and especially lower Tonner Canyon could have severe impacts on corridor function, especially if they reduced use of the Tonner Canyon Bridge on Highway 57.

Any development that blocked access to or through the bridge area would make Highway 57 a barrier to wildlife and likely lead to wildlife extirpations in segments farther west.

At the very least, creation of these reservoirs would incrementally reduce the size of what is now a large Chino-Tonner subcore. Tonner Canyon, representing the westernmost portion of this subcore, is the primary source habitat for animals dispersing into the rest of the corridor system to the west. Hence, the location of this project would magnify its relative impact on continued corridor function by increasing the distance wildlife would have to move from source habitat areas to other segments.

Proposed City of Industry Road
Figure 6 also shows an approximate, conceptual alignment for a proposed road parallel to Tonner Canyon (see also Maps 1 and 2). Although I found no specifications for this road or associated development, it would appear to be a major throughway connecting Highway 57 (from the existing Tonner Bridge intersection) to Highway 60 across the widest portion of the PuenteChino Hills Wildlife Corridor. Based on its location, the road would require major cut and fill to construct. Perhaps most troubling is its connection at the critical Tonner Bridge wildlife undercrossing. Depending on design, this is highly likely to render this last remaining corridor connection non-functional for mountain lion, deer, bobcat, and numerous other species. Even if this connection could be engineered to retain a functional wildlife undercrossing, the road could severely impact wildlife populations and movements along a broad front. A series of additional undercrossings (or overcrossings) and extensive wildlife fencing would need to be incorporated along the length of the road, or else most of Tonner Canyon would be isolated between two barrier roads (this one and Highway 57) or wildlife would suffer severe roadkill impacts.

Approximately 21.2 sq. km of grasslands, forests, and shrublands would be segregated from the large and valuable Chino-Tonner subcore, incrementally diminishing its capacity to support wildlife populations. At best, what is now a broadly contiguous block of habitat would be reduced to a narrow and more edge-effected funnel across the Olinda Landfill to the Tonner Bridge.

Cumulative Effects
A full impact analysis for any or all of these proposed projects would need to address cumulative impacts on wildlife populations and movements through the corridor, which is beyond the scope of this report. Among these cumulative impacts would be inducement of further development, Puente-Chino “Missing Middle” Analysis
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such as additional residential, commercial, or industrial development along the road. Increased traffic (and hence roadkill) would also need to be analyzed and mitigated for. Any combination of two or more of these projects would likely render the Puente-Chino Hills Wildlife Corridor non-functional west of Olinda Landfill, regardless of mitigation.

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Discussion
Before summarizing conservation and restoration recommendations for the Missing Middle, this section reviews the literature on the functions and benefits of wildlife corridors in conservation, including criticisms of corridor conservation.

Functions and Benefits of Wildlife
Corridors
Landscape linkages and wildlife movement
corridors vaulted to the forefront of conservation
thinking in recent decades, in response to rising recognition that habitat fragmentation is a principal cause of species extinction and endangerment (Willis 1974, Diamond 1975, Wilson and Willis 1974, Noss 1983, Wilcox and Murphy 1985, Forman 1991, Harrison 1992, Rosenberg et al. 1997). Habitat connections or movement corridors connecting reserves or larger “core areas” of habitat are thought to counter many adverse effects of isolation by fragmentation on species and ecological processes (Preston 1962, Noss 1983, 1987, Soulé 1991, Meffe and Caroll 1994, Rosenberg et al. 1997, Soulé and Terborgh 1999, Beier et al. in press). Although some critics have argued that there are costs as well as benefits to conserving corridors, and that under certain circumstances creating or maintaining corridors could even harm some species or communities (e.g., Simberloff and Cox 1987, Simberloff et al. 1992, Hess 1994), the overwhelming weight of scientific evidence is that maintaining connectivity is generally beneficial, especially for those species and ecological communities for which connectivity “is the natural state of things” (Soulé and Terborgh 1999). Certainly, for most species and ecological communities, maintaining connectivity is less risky than losing connectivity (Hobbs 1992, Beier and Noss 1998, Soulé and Terborgh 1999).

Assessing Connectivity Pros and Cons
This section reviews specific arguments for and
against conserving corridors and how they apply to the
Puente-Chino Hills. As elaborated below, in most
cases, arguments against corridor conservation are
really just cautions against applying corridors as a
panacea for conservation, in recognition that there may be special cases where connecting reserves could cause more harm than good or where other approaches to conservation may be more effective or cost-effective (for example, enlarging core reserves rather than connecting existing reserves). These special cases do not apply to the Puente-Chino Hills Wildlife Corridor, where maintaining connectivity would clearly provide net benefits for biological diversity and ecosystem health in these hills. Given that the weight of scientific evidence favors connectivity here, whether and how connectivity can be assured is a societal issue not addressed in this scientific treatment. “Those who would destroy the
last remnants of natural
connectivity should bear the
burden of proving that corridor
destruction will not harm target
populations.”
Paul Beier & Reed Noss (1998)
“Connectivity is not just another
goal of conservation: it is the
natural state of things.”
Michael Soulé & John Terborgh (1999)
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The potential disadvantages of creating or maintaining wildlife movement corridors include several ecological arguments and one financial argument (Simberloff and Cox 1987, Simberloff et al. 1992, Hobbs 1992, Hess 1994):

1. Corridors may serve as conduits for the spread of deleterious species, like invasive pests, weeds, or predators.

2. Corridors may serve to spread detrimental processes—such as wildfire or disease—to or among reserve areas.6

3. Corridors may facilitate movements by highly mobile animals between reserves even without corridors. (Or, these species may be overly abundant in urban interface areas due to imbalanced ecological conditions.) But corridors may not help movement for more sedentary or at-risk species, for which other conservation approaches may work better than corridors.

4. Corridors could act as population “sinks” (Pulliam 1988), attracting individuals from higher quality habitat areas into edge-effected habitats where death rates exceed birth rates. If this effect is strong enough, it can reduce the regional abundance of the species, or even increase extinction probabilities for a rare species.

5. Corridors may be expensive to create or maintain and may not represent the optimal allocation of limited funding relative to, for example, increasing the size or management of existing core areas.

Note that in one way or another, all of these potential disadvantages hinge on relative comparisons of potential risks and benefits of maintaining vs. losing connectivity. Also, as pointed out by numerous researchers, the risks and benefits of corridors will vary by species. In the sections below, I briefly evaluate these potential disadvantages as they may apply within the Puente-Chino Hills Wildlife Corridor for target species of interest.

Conduits for Deleterious Species
It is difficult to envision how any deleterious species might increase its distribution or adverse effects due to conserving additional lands in this existing archipelago of open space reserves.

Connecting these areas with additional conservation would not increase rates with which annual weeds, Argentine ants, rats, house mice, or other potential pest species invade open space areas relative to existing conditions. Sources of such deleterious species are nearly ubiquitous in Southern California, due to existing human land use patterns. Maintaining an existing open space corridor system would not facilitate expansions of such species, either from the more urbanized western portions of the study area into the Santa Ana Mountains, or vice versa, and may even help counter further invasions (relative to more roads or development in the area).

6 Although wildfire and disease are natural disturbance processes in ecosystems, changes wrought by humans, such as habitat fragmentation and increased fire frequencies in urban interface areas, may create situations where these natural processes cause unnatural harm to biological resources. Corridors could help spread these deleterious effects.

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Conduits for Deleterious Processes
Again, it is difficult to conceive how maintaining connectivity in this context could contribute to the spread of deleterious processes. This argument is generally based on the assumption that a new corridor is being created (e.g., connecting what are naturally unconnected habitat areas) rather than maintaining “the natural state of things” with an existing, natural corridor (Beier and Noss 1998). As with the argument concerning deleterious species, this seems not to be an issue for the Puente-Chino Hills Wildlife Corridor. Although diseases or parasites may be carried between habitat segments by wildlife, this already occurs and always did. Although fires may spread from one segment to another under certain conditions, the area is already highly segmented by fire breaks in the form of existing roads and other discontinuities. In fact, given the nature of Southern California’s most destructive wildfires, which are driven by Santa Ana wind conditions (Keeley and Fotheringham 2001, Keeley et al. 1999, Halsey 2004), fire provides a stronger argument for not building more homes in wildland areas, rather than an argument for not conserving wildland areas.

Ineffectiveness for Rare or Sedentary Target Species
This is clearly a non-argument for the Puente and Chino Hills. Target species selected for review in this report, including both rare and common species, are highly sensitive to habitat fragmentation and benefit from corridor conservation (e.g., Beier 1993, Beier et al. in press, Crooks 2002, Ng et al. 2004). Although some rare or more sedentary species may not benefit directly from corridor conservation here (e.g., some reptile and amphibian species already lost from western segments of the corridor), the ecological benefits that accrue from corridor conservation for the remaining flora and fauna are indisputable. Indeed, research in the PuenteChino Hills Wildlife Corridor reinforces other research indicating that more common, insensitive, and “pesky” wildlife like skunks and raccoons actually increase in density with reductions in larger carnivores like mountain lions and bobcats, due to losses of landscape connectivity (Haas 2000, Crooks and Soulé 1999). Countering this process of “meso-predator release” (Crooks and Soulé 1999), and the cascade of species losses and other adverse ecological changes that it can bring, is a strong argument for maintaining the Puente-Chino Hills Wildlife Corridor for mountain lions, coyotes, and bobcats.

Population Sinks
This is a legitimate argument that deserves analysis. It may be that, especially for species highly prone to roadkill, mortality in the Puente and Chino Hills is elevated relative to larger, more contiguous areas like the Santa Ana Mountains. It is conceivable that the corridor therefore serves as a “population sink” (Pulliam 1988), where animals enter the corridor from larger or higher quality habitats, only to be killed. However, the potential for this effect to substantially reduce regional wildlife populations in the Santa Ana Mountains seems remote. Moreover, the benefits of these species living within the Puente and Chino Hills, even with elevated mortality rates, are immense, both to ecological health and to quality of life for local human residents.

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Suboptimal Conservation Investment
This is a non-argument for this study area. Given the current wildland-development pattern that exists, there is no alternative to corridor conservation and restoration for retaining species populations and maintaining healthy ecological processes in this area. Although one could argue that further investment in conserving these hills could be better spent elsewhere (e.g., enlarging larger wilderness reserves in Southern California mountains), this would come at the detriment of maintaining a unique ecological classroom full of wildlife in close proximity to millions of people craving a connection with nature. According to the California Department of Parks and Recreation, nearly a quarter billion dollars have already been spent on open space conservation in the Puente and Chino Hills, and this investment could be for naught if additional conservation fails to secure a continuous corridor from the Santa Ana Mountains to the Whittier Hills.

Mitigating Road Effects
Roads or the traffic they carry kill animals directly
(roadkill), disrupt natural migration and movement
patterns, interfere with species communication, change
water runoff and flow patterns, and create air, water, and soil pollution (Trombulak and Frissell 2000, Forman and Deblinger 2000, Jones et al. 2000, Reijnen et al. 1997). During Beier’s (1993, 1995) study of mountain lions in the Santa Ana Mountains, vehicles killed 33% of the population, including four lions killed at one road-crossing during a 2-year period.

The growing awareness of road impacts on environmental health and imperiled species has created a burgeoning literature on efforts to mitigate these effects with improved wildlife roadcrossing structures. Wildlife crossing structures have proved successful in the United States and elsewhere (Transportation Research Board 2002). The main types of structures, from most to least effective, are vegetated land-bridges, bridges, underpasses, and culverts.

About 50 vegetated wildlife overpasses, ranging from 50 m (164 ft) to over 200 m (656 ft) wide, have been built in Europe, Canada, and the U.S. (Evink 2002, Forman et al. 2003). Soil (0.5 to 2 m deep) covers the overpasses, which are planted, usually with native vegetation (Jackson and Griffin 2000). Overpasses are quieter than underpasses and maintain ambient conditions (Jackson and Griffin 2000), so they may be less intimidating for some species than dark tunnels.

In Banff Provincial Park, large mammals preferred overpasses to other crossing structures (Forman et al. 2003). Similarly, birds, butterflies, and other open-air wildlife are more likely to use overpasses than underpasses.

Bridges are also effective crossing structures, especially if wide enough to permit growth of both riparian and upland vegetation along stream banks (Jackson and Griffin 2000, Evink 2002, Forman et al. 2003). Bridges with greater openness ratios are generally more successful than low bridges and culverts (Veenbaas and Brandjes 1999, Jackson and Griffin 2000). The Tonner Bridge is a good example of a broad, open bridge with natural vegetation beneath. My observations reinforce those of previous biologists that maintaining access through this structure, “Nothing is worse for sensitive
wildlife than a road.”
Reed Noss
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and perhaps improving habitat conditions on either side, is critical to the flow of large mammals across the Puente-Chino Hills landscape.

Although inferior to bridges, culverts and other tunnel-like structures can be effective for some species (Jackson and Griffin 2000). Only very large culverts (such as box culverts and equestrian tunnels) are effective for large mammals (Lyren 2001, Haas 2000, Gloyne and Clevenger 2001). Gloyne and Clevenger (2001) suggest that underpasses for ungulates should be at least 4.27 m high and 8 m wide, with an openness ratio of 0.9 (where the openness ratio = height x width/length). Earthen flooring is preferable to concrete or metal (Evink 2002).

In places where a bridged, vegetated under-crossing or over-crossing is not feasible, placing pipe culverts alongside box culverts can help serve movement needs of both small and large animals.

Special crossing structures that allow light and water to enter the structure have been designed to accommodate amphibians.

Noise, artificial night lighting, traffic noise, and other disturbances can deter animal use of a crossing structure (Yanes et al. 1995, Clevenger and Waltho 1999, Forman et al. 2003). Shrub or tree cover can help funnel wildlife to a passage while hiding them or making them feel more secure when approaching crossing structures (Evink 2002, Forman et al. 2003). Regardless of crossing type, wildlife fencing is necessary to funnel animals towards road-crossing structures and keep them off the road surface (Falk et al. 1978, Ludwig and Bremicker 1983, Feldhammer et al. 1986, Haas 2000, Lyren 2001, Forman et al. 2003). Earthen one-way ramps can allow animals that wander into the right-of-way to escape over the fence (Bekker et al. 1995, Forman et al. 2003).

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Conclusions and Recommendations
Conservation and Restoration Priorities for the Missing Middle Based on the analysis of corridor function, Map 3 shows locations of priority conservation and restoration actions in and near the Missing Middle. This is by no means a comprehensive summary of all necessary and sufficient actions to maintain or improve biological conditions throughout the Puente-Chino Hills landscape. Rather, it focuses on those locations and actions that seem most critical to maintaining functional connectivity across the Puente-Chino Hills Wildlife Corridor based on the metapopulation analysis.

These recommendations are redundant with those from previous studies, especially concerning the need to secure and improve unimpeded movement by large target species across roads. This should not be surprising, because information on the characteristics and functioning of these corridor segments is quite consistent across studies. Perhaps the greatest benefit of the metaanalysis provided in this report is a renewed focus on the need to conserve not just unimpeded movement, but an archipelago of relatively large habitat blocks with sufficient carrying capacity to ensure continued presence of viable populations through this range of hills. Road-crossings are just one part of the story.

Priority Conservation Lands
Conserving intact habitat blocks within the red-hatched lands on Map 3 is essential to maintaining functional metapopulation dynamics for target species throughout the Puente-Chino Hills Wildlife Corridor. As supported by the geographic unit analysis, the capacity of Segments 2 and 3—from Chino Hills State Park to Harbor Boulevard—to support robust populations of target species and live-in habitat for mountain lions is essential to keeping these species in the study area, all the way to Whittier Hills. Essentially all of the Shell-Aera property, and at least the lower 1/2 to 2/3 of the City of Industry lands in Tonner Canyon, are of high priority for conservation.

Note that the line separating high-priority conservation lands in mid- to lower Tonner Canyon from upper Tonner Canyon is somewhat arbitrary. But the farther up Tonner Canyon one goes, the less essential habitat becomes for ensuring corridor functionality. (Note, however, that Cooper [2000] considered upper Tonner Canyon a high conservation priority for native birds, especially grassland species like raptors and grasshopper sparrows.) I established the northeast boundary of the Tonner Canyon high-priority conservation area primarily to consolidate a contiguous reserve along with the existing Firestone Scout Reservation and Chino Hills State Park. Extending this boundary farther north would increase biological benefits even more, but with decreasing marginal returns for corridor function.

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Map 3. Conservation and restoration priorities in the vicinity of Missing Middle.

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Essentially all of the Shell-Aera property west of Highway 57 is extremely high priority for conserving corridor integrity. Based on metapopulation analysis, conserving a “move-through corridor” across this property, as depicted in Figure 5, is not enough to ensure continued target species presence through the corridor system. Given this segment’s location between two nearbarrier roads, and the relatively narrow and constrained status of Segments 4 and 5 to the west, securing a large, intact habitat block capable of supporting populations or subpopulations of target species is essential here. Moreover, this segment could benefit greatly from habitat management and restoration to increase carrying capacity for target species, and thereby to decrease the probability of species extirpations here and all the way to the Whittier Hills.

Priority Crossing Improvements
Map 3 shows five priority road-crossing improvements with magenta circles, labeled A through E from east to west. Most of these recommendations have already been made by others (e.g., Haas 2000), and some may already have been acted on or are in planning stages. At the risk of redundancy, I nevertheless recommend the following improvements in these general locations.

Refer to Haas (2000) for additional recommendations and details:

A. Add wildlife fencing on either side of Carbon Canyon Road to reduce roadkill and encourage wildlife to use existing culverts, especially the concrete box culvert near the entrance to Chino Hills State Park. Adding another wildlife crossing structure, designed to accommodate all large mammals, would be even better. Given that traffic on this 2- lane road is increasing due to increasing development in the vicinity (Haas 2000), any future road upgrades should incorporate bridges or other very open wildlife crossing structures as mitigation. A variety of smaller under-crossings with funneling fences, specifically designed to accommodate smaller reptiles, amphibians, and mammals, should also be considered to improve connectivity for these species.

Fence along Highway 57 if monitoring suggests road mortality is high.

C. A wildlife underpass tunnel is to be constructed here under Harbor Boulevard, but recommended fencing has apparently not been allowed by a property owner (A.

Henderson, personal communication). Secure rights to install wildlife fencing along both sides of Harbor Boulevard to reduce roadkill and ensure maximum utility of the wildlife tunnel. Plant native shrubs and trees on either side of the tunnel to provide cover to wildlife approaching the entrances. Consider adding smaller under-crossings and funneling fences to accommodate smaller reptiles, amphibians, and mammals.

D. Secure remaining “at-risk” parcels in this narrow, constricted portion of the corridor, west of Powder Canyon and Schabarum Regional Park. Enlarge or otherwise improve the existing equestrian tunnel to enhance its use by wildlife, including adding screening Puente-Chino “Missing Middle” Analysis
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vegetation, especially on the western end. Fence either side of the tunnel to help funnel wildlife to it. However, extensive fencing along Hacienda Boulevard is not recommended, because most large mammals currently cross at-grade. Although Hacienda Boulevard currently has moderate traffic at relatively low speeds, and therefore relatively low roadkill (Haas 2000), road improvements or increases in traffic could make the situation worse. In this case, consider building a wildlife overpass (a vegetated wildlife bridge) over Hacienda Boulevard, taking advantage of steep slopes rising up from either side of the road. Given this terrain, a vegetated overpass somewhere between Skyline Drive and the equestrian tunnel may be feasible and would certainly be superior to culverts or other underpass structures in accommodating wildlife movement. Consider also adding smaller under-crossings and funneling fences to accommodate smaller reptiles, amphibians, and mammals.

E. Maintain and improve the Colima Service Tunnel as a critical wildlife underpass. Add fencing or screening vegetation, if necessary, based on further site-specific inspection or monitoring. Limit and mitigate for any actions that may increase traffic, light, noise, or human activity in the vicinity of the Service Tunnel from sunset to sunrise, when wildlife use is most frequent. Consider also adding smaller under-crossings and funneling fences to accommodate smaller reptiles, amphibians, and mammals.

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Exhibit C

Exhibit D

Exhibit E

Exhibit F

Exhibit G

manatt
404613130.1
March 27, 2026
VIA EMAIL ([email protected])
City of Brea
Planning Division
1 Civic Center Circle
Brea, CA 92821
Re: General Plan Comments for Brea 2050: Focused GPU and BCSP (State Clearinghouse No. 20250811123)
To Whom It May Concern:

This firm represents Sycamore Development Brea Canyon LLC and its affiliates (“Sycamore”), and we submit this letter on Sycamore’s behalf in connection with the City of Brea’s (“City”) Brea 2050: Focused General Plan Update (“2050 GPU”).1

Sycamore owns a significant amount of real property within the County of Orange (“County”), and certain of that real property is wholly or partially within the City’s Sphere of Influence (“SOI”) as shown in the 2050 GPU. Specifically, Sycamore owns approximately 321 acres located east of Brea Canyon Road and north of State Route 57 (hereinafter, the “CA-57 North Property”)2 and approximately 297 acres of property located south of Valencia Avenue and east of Carbon Canyon Road (hereinafter, the “Carbon Canyon Property”).3 The County
currently holds jurisdiction over the CA-57 North Property in its entirety and the majority of Carbon Canyon Property.

The CA-57 North Property, along with Sycamore’s adjacent lands in County of Los Angeles, is presently developed with more than 100 well sites, produces approximately 155 barrels of oil and 200 million cubic feet of natural gas per day, and is blanketed by an extensive network of production infrastructure, including tank facilities, processing facilities, service roads, and power lines. Additional industrial activities, including truck rental and servicing operations, also take place on the CA-57 North Property. The CA-57 North Property is designated for “Hillside Residential” in the City’s operative general plan adopted in 2003 (“2003 General Plan”), and the 2050 GPU proposes to maintain this Hillside Residential designation as to the CA-57 North Property.
1 The 2050 GPU was first made available to the public on February 12, 2026. 2 The CA-57 North Property is more specifically identified as parcel numbers 304-151-05, 304-151-10, 304-151-12, 304-151-14, 304-151-17, 304-151-18, 304-151-19, 304-151-69, 304-171-03, 304-171-06, 304-171-07, 304-171-08, 306-011-01, 306-011-02, 306-011-03, 306-012-12, 306-012-13, and 306-013-01. 3 The Carbon Canyon Property is more specifically identified as parcel numbers 308-021-15, 308-021-21, 308-011- 20, 308-011-22, 315-081-09, 312-011-18, 312-011-19, 322-031-29, 322-041-24, 322-051-12, 326-011-03, 326-011-

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Portions of the Carbon Canyon Property were previously utilized for oil and gas exploration and production activities and the majority of the Carbon Canyon Property is also designated for Hillside Residential uses in the 2003 General Plan. The Carbon Canyon Property remains in a disturbed, largely idled industrial state associated with historic oil and gas operations, although portions of the property may ultimately be appropriate for open space preservation, habitat connectivity, or other conservation treatment through a future site-specific planning process. The 2050 GPU proposes to maintain this Hillside Residential designation as to the Carbon Canyon Property.

One of the parcels amongst the greater Carbon Canyon Property complex is an approximately 25-acre parcel commonly referred to as the Olinda Drive parcel and more specifically identified by APN 315-081-09 (hereinafter, the “Olinda Drive Property”). The Olinda Drive Property abuts a residential development known as the Olinda Village and Olinda Drive, which currently services Olinda Village residents. In 1998, Olinda Drive was extended via a recorded easement between the City and the Olinda Drive Property owner, making it possible for Olinda Drive to serve future residential development on the Olinda Drive Property. The various commitments made between the City and the Olinda Drive Property owner with respect to residential redevelopment are discussed more fully below.

The principal purpose of these comments is to provide the City with a redevelopment template for the CA-57 North Property and the Carbon Canyon Property that would allow the City and Sycamore to coordinate on future redevelopment. These comments also identify defects in the 2050 GPU and the Draft Program Environmental Impact Report (“Draft PEIR”). We request that the City: (1) revise the 2050 GPU to preserve and facilitate the use of a future specific plan framework for the CA-57 North Property and the Carbon Canyon Property, as described below; and (2) correct the errors and deficiencies identified in this letter. Sycamore further requests that this letter, together with all attachments, be included in the administrative record for the 2050 GPU and Draft PEIR.

I. The Brea 265 Project: A Proven Specific Plan Framework for Coordinated Redevelopment and Conservation
a. Any Future Redevelopment Involving Sycamore Lands Should Replicate the Brea 265 Project Process
The Brea 265 Project provides a proven local precedent for the type of flexible, sitespecific planning framework that is appropriate for Sycamore’s properties. The Brea 265 Project resulted from a collaborative planning process that began between the City and the property owner in 2018 and culminated in City approval of the Brea 265 Specific Plan under General Plan Amendment, Zone Change, Specific Plan and Development Agreement No. 2022-01 adopted in Ordinance Nos. 1229 and 1230 on August 16, 2022 and Resolution Nos. 2022-058, -059, and - 060 on July 19, 2022 and an Environmental Impact Report under State Clearinghouse Number 2018121035 (the “Brea 265 Project”). Through that process, the City converted approximately 265 acres of formerly active oil field land of varied topography into a comprehensively planned City of Brea Planning Division
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community that balances housing production, open space preservation, environmental mitigation, and infrastructure coordination.

The Brea 265 Project demonstrates how residential density can be distributed across a site with varying topography and environmental sensitivity through coordinated master planning, rather than rigid, parcel-by-parcel density limitations. Under the 2003 General Plan, the Brea 265 Project site was designated “Hillside Residential” and “Low Density Residential” prior to the City’s adoption of the specific plan. The Brea 265 Specific Plan allows up to 1,134 dwelling units – approximately 4.2 dwelling units per acre overall – through a mix of clustered low- and medium-density residential areas integrated with open space preservation and conservation planning.

The Brea 265 Specific Plan implements a flexible regulatory framework that allows residential density to be distributed strategically across the site rather than strictly limited by localized slope conditions as otherwise contemplated in “Hillside Residential” areas. A portion of the site east of Valencia Avenue slopes from northeast to southwest with more than 150 feet of elevation change. (Brea 265, page 2-12.) Residential uses are designated as “Low Density” (1.0-6.0 dwelling units per acre) and “Medium Density” (6.1-12.0 dwelling units per acre), which average approximately 4.2 dwelling units per acre across the site. (Brea 265 Table 3-1, page 3-2.) Through the specific planning process, 47 acres have been designated as open space, and density transfers are permitted as part of a phased development. In addition, the Brea 265 Project resulted in the permanent conservation of approximately 81 additional acres through recorded offers of dedication in favor of Chino Hills State Park or an alternative land steward, for a total of approximately 128 acres of preserved or protected land.

As reflected in the Brea 265 Project’s objectives, the Specific Plan is intended to “provide flexibility in plan implementation to allow for changes in future market conditions” and to promote “creative approaches to development and use of land through variation in building siting and combining appropriate land uses, activities and housing types.” (Brea 265 pages 1-3 and 2-4.) Importantly, the Brea 265 Project demonstrates why a specific plan is the appropriate planning tool for a site of this nature. The site involved a formerly industrial oil field with substantial areas of disturbance and limited conservation value, alongside portions with moderate to higher environmental sensitivity. The specific plan framework allowed the City to direct redevelopment to the disturbed areas while preserving and protecting areas with greater resource value, resulting in a coordinated plan that both accommodates housing and secures meaningful conservation outcomes.

A similar pattern exists on Sycamore’s properties. Substantial portions of the Carbon Canyon Property are already subject to recorded conservation protections. These existing constraints further underscore the need for a comprehensive planning approach that can coordinate preservation and development across the property as a whole.

Accordingly, the City should recognize the Brea 265 Project as a strong local precedent supporting a comprehensive, site-specific planning approach for properties proposed to be designated “Hillside Residential” in the 2050 GPU. The 2050 GPU presents a similar City of Brea Planning Division
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opportunity for the City to maintain long-term planning flexibility for properties within the SOI, including Sycamore’s properties, by acknowledging that future annexation or redevelopment proposals may be more appropriately addressed through a specific planning process rather than through inflexible application of the Hillside Residential designation alone. b. Redevelopment Consistent with the Brea 265 Project Will Fulfill Key City Policies, Objectives and Housing Needs for the Next Two Decades The 2050 GPU establishes a long-term planning framework that must be evaluated not only in light of current conditions, but also in anticipation of future housing needs and multiple upcoming housing cycles over the life of the General Plan. While the City’s current Housing Element remains in effect, the GPU’s 2050 horizon necessarily contemplates continued population growth, evolving land use demands, and the need to identify sites capable of accommodating future residential development in a manner that is both efficient and environmentally responsible.

Consistent with this long-term planning framework, the 2050 GPU includes numerous policies that support flexible, site-specific planning approaches rather than rigid application of generalized land use designations.

Policy CD-1.1: Land Use Pattern. Provide a coordinated mix of housing, employment, service, and recreational opportunities that encourages efficient development and multimodal choices; minimizes environmental impacts; ensures land use compatibility; enhances community livability and public health; and sustains economic vitality. (2050 GPU page 59.)
Policy CD-1.2: Housing Options. Support a diverse range of housing development options and densities, ensuring that residents across income levels, age groups, and those with special needs can live within the community. (2050 GPU page 59.) Policy CD-1.5: Employment/Housing Balance. Strive to balance employment and housing levels within the community to create more opportunities for residents to work locally. A balanced jobs-to-housing ratio enables residents to live and work in Brea, fostering a greater sense of community and convenience. (2050 GPU page 59.) Policy CD-1.7: Development Flexibility. Allow for flexible development standards in the City’s Zoning Ordinance provided that the potential benefits and merits of projects can be balanced with potential impacts. (2050 GPU page 59.) Policy CD-1.8: Sustainable Development Practices. Implement policies and programs that encourage the efficient use of land and infrastructure to reduce environmental impacts and support long-term community sustainability. (2050 GPU page 59.) Policy CD-6.5: Growth Pattern. Strongly encourage new development in infill locations in a balanced and efficient pattern that reduces sprawl, preserves open space, and creates City of Brea Planning Division
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convenient connections to other land uses and transportation facilities. (2050 GPU page

70.)
Policy ED-1.1: Land Uses. Maintain and expand the City’s opportunities to support diverse businesses by identifying opportunity sites for residential and commercial development that align with regional market demand. (2050 GPU page 231.) Action ED-1b: Periodically conduct a survey of vacant, underdeveloped, and underutilized sites, and engage with property owners regarding business attraction efforts or redevelopment opportunities. (2050 GPU page 232.)
Action ED-1d: Improve the marketability of opportunity sites through infrastructure improvements, regulatory flexibility, financial incentives, and the promotion of Brea’s market advantages. (2050 GPU page 232.)
Action ED-2f: Integrate the business community’s interests into City’s legislative advocacy work or collaborate to pursue and finance local economic development efforts. (2050 GPU page 234.)
Policy ED-3.3: Develop land use policies that facilitate the development of housing affordable to a range of household types and incomes to diversify the local labor force and promote long-term residential stability. (2050 GPU page 235.) These policies collectively emphasize flexibility, efficient land use, and the need to accommodate a range of housing types through planning approaches that respond to site-specific conditions rather than rigid application of generalized land use designations.

Further, the 2050 GPU expressly recognizes the need to allow continued economic use and adaptive reuse of hillside properties.
“Most properties in the hills are privately held and the City must allow property owners to achieve some economic value from their lands, either by continuing to extract the oil resources buried in the hillsides or by transitioning the properties, where safe to do so, to some other economically viable use.” (2050 GPU page 46.) At the same time, the 2050 GPU contains goals, policies and actions that ensure any such transition occurs in a manner that protects environmental resources and addresses site-specific constraints – objectives that are inherently aligned with a comprehensive specific plan process.

Policy CD-4.2: Constraints. Base allowable development on the ability of infrastructure, landform, physical constraints, and emergency response capabilities to support new development. (2050 GPU page 65.)
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Action CR-4a: Assess development proposals, including those in Brea’s Sphere of Influence, for potential impacts to important visual resources pursuant to CEQA.4 Require appropriate mitigation measures for all significant impacts. Consider important ridgelines, creeks, open space, views of the surrounding hillsides, and light and glare effects. (2050 GPU page 153.)
Action PS-1.f: Design development on hillsides and canyons to reduce the increased risk of fires from topographic features (e.g., steep slopes, ridge saddles). (2050 GPU page 203.)
Action PS-1.g: Review proposed development projects and street networks to evaluate the accessibility for fire engines and other emergency response functions. (2050 GPU page 203.)
Policy PS-2.2: Hillside Development. In areas subject to the City’s Hillside Zoning Ordinance, require a full site-specific geologic study to consider effects of the proposed development on adjacent upslope and downslope areas as well as on the site itself. (2050 GPU page 204.)
Policy PS-4.7: Oil Fields. Work closely with responsible State and Federal agencies to ensure that active oil field operations comply with all current regulations and, once oil field operations cease, that appropriate closure and clean-up activities occur. (2050 GPU page 210.)
The 2050 GPU emphasizes coordinated long-term planning for lands within the City’s SOI, including through annexation where appropriate. Specifically, the 2050 GPU includes these supporting policies:

Policy CD-1.11: Multi-Jurisdictional Coordination. Coordinate with neighboring jurisdictions to ensure land use compatibility in areas surrounding Brea. Partnerships with Orange County and adjacent cities can support the development of cohesive strategies to address regional planning challenges and development. (2050 GPU page 59.) Policy CD-1.12: Annexations. Strongly consider the annexation of adjacent unincorporated properties in the City’s Sphere of Influence (SOI) and avoid the creation of any new County islands. (2050 GPU page 59.)
Policy CD-4.5: Regional Coordination. Coordinate with Orange County and emphasize the City’s need to participate in the development review process of projects proposed in surrounding unincorporated areas. Work to ensure that such developments proceed consistent with City standards. (2050 GPU page 65.)
4 As used herein, “CEQA” means and refers to the California Environmental Quality Act.

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Policy CD-6.8: Interregional Cooperation. Cooperate with other agencies to address regional issues and opportunities related to growth, transportation, infrastructure, and other planning issues. (2050 GPU page 70.)
Taken together, these policies establish that the City’s long-term planning objectives are best achieved through flexible, site-specific planning approaches that can respond to unique site conditions, accommodate future housing needs, and balance development with environmental protection. As demonstrated by the Brea 265 Project, a comprehensive specific plan framework provides the appropriate mechanism to implement these policies by allowing the City to direct development to suitable areas while preserving environmentally sensitive lands. Maintaining this type of planning flexibility for Sycamore’s properties is therefore not only consistent with the 2050 GPU’s stated policies, but necessary to ensure the City can effectively plan for future growth over the life of the 2050 GPU.

The City’s adopted 2021-2029 Housing Element already establishes the implementation expectation for addressing future housing needs through annexation and comprehensive, sitespecific planning. The goals and policies in the Housing Element expressly commit the City to providing “adequate housing sites through appropriate land use, zoning, and specific plan designations” as well as through the pursuit of phased annexation of lands within the SOI. (Housing Element page 3-164, emphasis added.) Such goals and policies include the following:

Goal 2.0: Assist in the provision of adequate housing to meet the needs of the community. Establish a balanced approach to meeting housing needs that includes the needs of both renter and owner households. (Housing Element page 3-163.) Policy 2.5: Public/Private Partnerships. Explore collaborative partnerships with major employers, educational institutions, non-profit organizations, and others in the provision of affordable, workforce and special needs housing. (Housing Element page 3-163.) Goal 3.0: Provide adequate housing sites through appropriate land use, zoning, and specific plan designations to accommodate Brea’s share of regional housing growth needs. (Housing Element page 3-164.)
Policy 3.6: Hillside Development. Base densities in Brea’s hillsides on the ability of infrastructure, ingress and egress for evacuations, landform, physical constraints, and emergency response capabilities to support development. (Housing Element page 3-164.) Policy 3.7: Annexations. Pursue phased annexation of Brea’s Sphere of Influence to provide additional growth opportunities for a range of housing types consistent with infrastructure capacities. (Housing Element page 3-165.) Goal 4.0: Reduce potential governmental constraints to housing production and affordability. (Housing Element page 3-165.)
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Policy 4.2: Flexible Development Guidelines. Provide flexibility in development/design guidelines to accommodate new models and approaches to providing housing, such as transit-oriented development, live/work housing, micro units and flex space to allow housing to adapt to the needs of the occupants. (Housing Element page 3-165.) Goal 6.0: Promote a healthy and sustainable Brea through support of existing and new housing which minimizes reliance on natural resources and automobile use. (Housing Element page 3-167.)
Policy 6.6: Jobs/Housing Balance. Encourage a closer link between housing and jobs in the community, including housing opportunities affordable to Brea’s modest income workforce. (Housing Element page 3-167.)
These policies were actively implemented through the approval of the Brea 265 Project, which converted a large, formerly industrial property having varied topography within the SOI into a comprehensively planned residential community. The Brea 265 Project now accounts for a substantial portion of the City’s certified housing capacity under the Housing Element. Having successfully relied on that framework to meet its current RHNA obligations, the City has already demonstrated that annexation paired with a specific plan is an effective mechanism to deliver housing in constrained hillside areas.

The 2050 GPU will extend well beyond the current Housing Element cycle and necessarily must anticipate multiple future housing cycles, each of which will require the City to identify and enable additional sites capable of accommodating residential development. The fact that the City has met its current RHNA largely by relying on the Brea 265 Project only underscores this obligation. The CA-57 North Property and Carbon Canyon Property represent the same category of opportunity sites the Housing Element contemplates for future cycles: large formerly industrial lands within the SOI that cannot be effectively planned or fairly evaluated through rigid, generalized land use designations blanketed across entire parcels. Upon annexation, a specific plan is therefore not merely an optional entitlement path, but the logical and policy-consistent tool for implementing the City’s adopted Housing Element commitments and long-range goals under the 2050 GPU – allowing housing capacity to be planned holistically, environmental constraints to be addressed comprehensively, and growth to be directed in a manner that is both defensible and executable over the long term. Therefore, we recommend a new “Future Specific Plan” land use designation for the CA-57 North Property and Carbon Canyon Property, inclusive of the Olinda Drive Property, in the 2050 GPU. c. The City Should Incorporate a Forward-Looking Specific Plan Framework for the Sycamore Properties in the 2050 GPU, in Particular, the Olinda Drive Property
The Brea 265 Project demonstrates that the City has successfully implemented a coordinated planning process to address the redevelopment of large, complex hillside and formerly industrial properties. That process allowed the City to comprehensively evaluate site conditions, balance development and conservation objectives, and establish a tailored regulatory City of Brea Planning Division
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framework for long-term buildout in a coordinated manner that aligned land use planning, environmental review, infrastructure considerations, and the transition of formerly industrial lands to residential use.

As reflected in the 2050 GPU’s annexation policies, including Policy CD-1.12, the City anticipates that lands within its SOI may be incorporated into the City over time. In that context, the 2050 GPU should not predetermine the ultimate development potential of such lands through rigid application of generalized land use designations. Rather, the City should recognize that properties such as the CA-57 North Property and the Carbon Canyon Property – characterized by a mix of previously disturbed areas and areas with varying environmental sensitivities – are more appropriately planned through a comprehensive, site-specific process. In addition, the existing pattern of disturbance, access, and infrastructure on both the CA-57 North Property and the Carbon Canyon Property provides a strong foundation for designing future development that meets applicable fire safety standards, including defensible space, emergency access, and fuel modification, through a coordinated specific plan process.

Importantly, Brea has previously recognized that annexation of SOI lands is intended to facilitate growth and housing production – not solely the preservation of open space. In connection with the Brea 265 Project, the City applied General Plan policies providing that it should “pursue phased annexation of Brea’s Sphere of Influence to provide additional growth opportunities for a range of housing types consistent with infrastructure capacities.” (Brea 265 Draft EIR, Table 5.11-2, Policy 3.7.) That policy reflects the City’s established approach of pairing annexation with comprehensive planning to accommodate housing and direct growth to appropriate locations, rather than limiting annexation to passive or preservation-oriented outcomes.

Consistent with that approach, any future annexation or redevelopment of Sycamore’s properties should be evaluated through a specific plan framework that allows the City to direct development to suitable areas, establish appropriate development standards, and secure preservation outcomes in an integrated and enforceable manner. This type of coordinated planning process would enable the City to implement its adopted policies related to housing, land use efficiency, environmental protection, and infrastructure planning holistically.

Importantly, the 2050 GPU presents an opportunity for the City to establish this planning framework proactively. Rather than deferring consideration of how such lands will be planned until a future annexation or project application, the City should incorporate policy language or other planning mechanisms within the 2050 GPU that acknowledge and preserve the use of a specific plan approach for large, undeveloped or underutilized properties within the SOI, including Sycamore’s properties. Doing so would provide clarity for both the City and property owners, reduce uncertainty in future planning efforts, and ensure that the City retains the flexibility necessary to address future housing and land use needs.

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This proactive inclusion of a forward-looking specific plan framework in the 2050 GPU is particularly appropriate for the Olinda Drive Property. The Olinda Drive Property is approximately 25 acres in size and has been earmarked for future residential development since approximately 1996-1998. This is evidenced by the April 8, 1998 Easement Agreement between the City and the Olinda Drive Property owner recorded as Instrument Number 19980206553, whereby the City extended Olinda Drive and domestic water pipelines onto the Olinda Drive Property to serve existing and future City residents. The anticipated residential redevelopment pathway for the Olinda Drive Property is also evidenced in the November 27, 1996 Quitclaim Deed to Phase One Property between the Olinda Drive Property owner and the State of California and identified as Instrument Number 19960607663. By way of that instrument, the Olinda Drive Property owner deeded other adjacent lands it owned to the State but specifically retained a three hundred (300) foot parallel buffer zone between the lands it deeded to the State and the Olinda Drive Property to facilitate “the use and development” of the Olinda Drive Property. Finally, the City’s and Sycamore’s present-day collaboration with respect to the Brea 265 Project also inures to the benefit of both current City residents and future City residents at the Olinda Drive Property. As the City is presumably aware, Sycamore is in the process of granting to the City 1,000 square feet of surface land on the Olinda Drive Property for the City’s construction and operation of an Activated Snorkel Station Heli-Hydrant for wildfire protection purposes. This installation will not only protect existing City communities, such as the Brea 265 Project community and the Olinda Village community but will also serve and protect future residents at the Olinda Drive Property.

In light of the foregoing, we ask that the City specifically include a specific plan designation or future specific plan designation or equivalent overlay in the 2050 GPU for the Olinda Drive Property. We also ask that such a designation be applied to the CA-57 North Property and the other parcels comprising the Carbon Canyon Property. To the extent that the City is not prepared at this time to adopt a formal overlay or designation specific to the CA-57 North Property or the Carbon Canyon Property parcels beyond the Olinda Drive Property parcel, the 2050 GPU should, at a minimum, avoid foreclosing the use of a comprehensive planning framework for these lands. Preserving this flexibility is consistent with the 2050 GPU’s stated policies and with the City’s demonstrated success in implementing the Brea 265 Project.

II. Planning and CEQA Comments on the 2050 GPU and Draft PEIR a. The 2050 GPU Relies on Outdated Hillside Planning Assumptions from the 2003 General Plan
As discussed above, while the City has demonstrated through the Brea 265 Project that complex hillside properties can be planned through a coordinated, site-specific process, the 2050 GPU instead appears to rely on legacy hillside planning assumptions that no longer reflect current conditions.

The 2050 GPU appears to carry forward land use assumptions derived from the City’s 2003 General Plan without sufficient re-evaluation of existing site conditions, infrastructure, or long-term planning objectives. In particular, the application of the Hillside Residential City of Brea Planning Division
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designation to the CA-57 North Property and the Carbon Canyon Property reflects an approach developed under materially different regulatory, environmental, and housing policy contexts.

As currently applied, the Hillside Residential designation presumes that hillside properties should remain limited to low-intensity, detached residential development or similar low-impact uses. While that framework may have been appropriate at the time it was adopted, it does not adequately reflect current conditions on the CA-57 North Property and the Carbon Canyon Property, including the presence of longstanding oil and gas operations, existing access and infrastructure, and varying levels of environmental sensitivity across the site.

Maintaining these legacy assumptions in the 2050 GPU risks constraining the City’s ability to plan effectively for future growth, particularly for properties within the SOI that may be annexed and redeveloped over the life of the General Plan. As demonstrated by the Brea 265 Project, a more flexible, site-specific planning approach allows the City to comprehensively evaluate site conditions, balance development and conservation objectives, and establish a tailored regulatory framework for long-term buildout.

Accordingly, Sycamore encourages the City to review these legacy designations and consider whether they continue to serve the City’s long-term planning objectives. Where policy assumptions from the 2003 General Plan no longer reflect current conditions, the 2050 GPU presents an opportunity to modernize those assumptions so that future planning efforts, including potential annexation or specific plan processes, can be evaluated based on accurate and current information.
b. Inaccurate and Unsupported Mapping in the 2050 GPU and Draft PEIR Several figures in the 2050 GPU and Draft PEIR appear to inaccurately depict or overstate conditions on the CA-57 North Property and the Carbon Canyon Property or otherwise rely on assumptions that do not reflect current site conditions. i. Figures 2-4 and 2-7 Do Not Accurately Reflect the Full Extent and Planning Context of the Carbon Canyon Property
Figures 2-4 (Current Zoning) and 2-7 (Proposed General Plan Land Use Designations) do not appear to fully and clearly reflect the Carbon Canyon Property, including remnant Sycamoreowned parcels in the Carbon Canyon area. Certain remnant holdings appear either to be omitted, generalized, or visually subsumed into surrounding open space or public land designations in a manner that does not accurately reflect Sycamore’s ownership or the planning context of those lands.

This issue is particularly important because the 2050 GPU relies on these citywide figures to establish the land use framework applicable to lands within and adjacent to the City’s SOI. At a minimum, the City should revise Figures 2-4 and 2-7 so that the Carbon Canyon Property, including Sycamore’s remnant holdings, is accurately shown and not visually conflated City of Brea Planning Division
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with surrounding lands that are already publicly owned, permanently preserved, or otherwise outside Sycamore’s control.
ii. Figure CR-3 (Wildlife Corridors) Overstates Corridor Functions and Relies on Unsupported or Non-Authoritative Mapping
Figure CR-3 in the 2050 GPU assigns large portions of the Sycamore properties a “Connectivity Rank” of “Irreplaceable and Essential Corridors,” relying in part on mapping attributed to Hills For Everyone. Hills For Everyone is a private advocacy organization, not a governmental agency with regulatory authority or a technical body charged with preparing adopted biological resource maps. To the extent the City is relying on this mapping to impose parcel-level planning constraints, such reliance does not appear to be supported by an identified technical or regulatory basis.

As to both the CA-57 North Property and the Carbon Canyon Property, the “Irreplaceable and Essential Corridors” overlay appears overly broad and not tied to current site conditions. The 2050 GPU should not assign such a severe corridor classification to Sycamore’s lands without identifying a reliable and site-specific technical basis for doing so. This mischaracterization also calls into question the adequacy of the Draft PEIR’s biological resources analysis to the extent that analysis relies on the same unsupported assumptions reflected in the mapping. Sycamore does not dispute that portions of the Carbon Canyon Property may support habitat or connectivity functions; however, the mapping does not adequately distinguish between previously disturbed areas and areas that may legitimately function as habitat corridors.

As to the CA-57 North Property specifically, the corridor depicted extending northward across the property appears to terminate in a dead end and to extend into Los Angeles County lands outside the City’s planning jurisdiction. If the City intends to depict regional connectivity concepts extending beyond its jurisdiction, the figure should clearly say so. Otherwise, the northern corridor extension should be deleted as erroneous.

As to the Carbon Canyon Property, the same figure overlays substantial portions of the property with the same “Irreplaceable and Essential Corridors” designation without sufficiently distinguishing between previously disturbed areas and any areas that may legitimately function as habitat connectivity. That undifferentiated treatment is not supported by the technical record as presently drafted.
iii. Figure 4.1-1 (Scenic Resources) Improperly Identifies Scenic View Corridors Over the CA-57 North Property
Figure 4.1-1 (Scenic Resources) appears to depict a scenic view corridor extending into the CA-57 North Property from the SR-57 corridor. Based on existing site conditions, that depiction does not appear to be supported. The relevant portion of the CA-57 North Property is characterized by active or legacy industrial uses, including truck servicing and rental operations, oil production infrastructure, and other disturbed industrial features. It is not an area appropriately characterized as a scenic view corridor.

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Accordingly, the scenic resource arrow extending into the CA-57 North Property should be removed. In addition, the northern scenic arrow appears to extend largely into Los Angeles County, beyond the City’s jurisdictional planning area. To the extent the City seeks to identify regional views beyond its jurisdiction, it should make that intent explicit. Otherwise, this northern view arrow should also be revised or deleted.

These inaccuracies also call into question the adequacy of the Draft PEIR’s aesthetics analysis to the extent that analysis relies on the same purported scenic views or corridors. More broadly, determinations regarding scenic resources on the Sycamore properties would be more appropriately evaluated through a future specific planning process supported by site-specific analysis, rather than through generalized citywide mapping at the GPU level. iv. The Vegetation Mapping Relies on Stale Source Data and Does Not Clearly Reflect Current Conditions on the CA-57 North Property The vegetation mapping used in the 2050 GPU and Draft PEIR appears to rely, at least in part, on source material prepared for the Nature Reserve of Orange County and a Johnson-Stokes study from 1992. Reliance on vegetation mapping that is more than three decades old raises significant concerns regarding the accuracy of the mapped vegetation communities on lands that have long been affected by oil and gas operations, industrial activity, grading, access roads, and other surface disturbances.

As to the CA-57 North Property, these outdated inputs appear to overstate the extent of undisturbed habitat conditions. Large portions of the CA-57 North Property have historically functioned as part of a disturbed oil field environment and are associated with well sites, service roads, equipment yards, truck operations, and other surface facilities. To the extent the vegetation mapping suggests more extensive natural or undisturbed habitat across these lands, the mapping is misleading and should be corrected. This characterization is also inconsistent with other figures in the 2050 GPU, including Figure PS-7, which accurately depicts the extent of active oil well infrastructure across the CA-57 North Property.

As to the Carbon Canyon Property, the figures appear in some respects to correctly identify disturbed conditions in at least portions of the property. Sycamore does not object to disturbed-area classifications to the extent they accurately reflect current site conditions.

However, the City should still disclose the source data and methodology used to draw the mapped habitat boundaries and should confirm whether any additional classifications – such as chaparral or other habitat types – are based on current, site-specific information rather than stale regional mapping.

To the extent the Draft PEIR relies on this vegetation mapping to characterize biological resources on the Sycamore properties, the adequacy of the biological resources analysis is similarly called into question.

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v. The City Should Revise Unsupported Local Figures but Need Not Resolve Here the Accuracy of Adopted State or Federal Maps Sycamore’s comments in this section are directed at local figures and overlays that appear unsupported, advocacy-driven, stale, or otherwise inaccurate as applied to the Sycamore properties. Sycamore does not challenge the legal validity of adopted state or federal resource maps, such as officially adopted fire hazard, critical habitat, or other regulatory maps prepared by agencies with statutory authority over those designations. However, where the City’s own figures go beyond those adopted maps or use them as a basis for unsupported parcel-level conclusions, the City should revise the figures accordingly and should not treat generalized or outdated mapping as a substitute for site-specific analysis. c. Internally Inconsistent Mapping of the Olinda Drive Property and other Portions of the Carbon Canyon Property as “Other Recreation” As discussed above, the 2050 GPU land use map designates Sycamore’s CA-57 North Property and its Carbon Canyon Property, inclusive of the Olinda Drive Property, for Hillside Residential uses. Despite the 2050 GPU’s designation of Sycamore’s lands for Hillside Residential uses, the 2050 GPU’s Figure CR-1 “Parks, Recreation Facilities and Open Space” purports to classify portions of the Carbon Canyon Property and all of the Olinda Drive Property as “Other Recreation.” Such classification conflicts with, and is inconsistent with, the Hillside Residential designation. Such Other Recreation designation would also conflict with and be inconsistent with any prospective specific plan designation applied to Sycamore’s lands. We request that the City correct this mapping error by removing Sycamore’s lands from the Other Recreation classification in Figure CR-1 to avoid creating an internal inconsistency within its general plan in violation of state planning and zoning law. Additionally, we note that such reclassification and the environmental consequences of such reclassification was not disclosed or analyzed in the Draft PEIR. Consequently, such reclassification would not comport with CEQA. d. The City’s Mischaracterization of Sycamore’s Properties Establishes an Improper Baseline under CEQA
The 2050 GPU and Draft PEIR repeatedly describe the SOI, including Sycamore’s properties, as “undeveloped” hillside open space and rely on that premise in the project description and impact analyses (e.g., hydrology and public safety). This framing effectively establishes the environmental baseline for the Draft PEIR’s impact analysis, yet it is not supported by parcel-specific documentation of existing conditions or a transparent methodology for the SOI buildout and capacity estimates. Under CEQA, an EIR must describe the physical environmental conditions in the vicinity of the project with sufficient detail to establish an accurate baseline for evaluating environmental impacts. (CEQA Guidelines § 15125.) A misleading or incomplete baseline and project description undermines informed public review and comment and warrants clarification or correction in the Final PEIR. Absent correction of the Draft PEIR’s assumptions regarding “undeveloped” SOI lands, the environmental analysis cannot serve as a sufficient foundation for the Planning Commission, which is scheduled to consider the 2050 GPU on April 14, 2026 or the City Council.

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In describing the characteristics of lands within the Planning Area (which includes the City’s jurisdiction and SOI), the 2050 GPU calls out Sycamore’s properties specifically:
“The hills north of Brea lie in unincorporated Orange and Los Angeles counties, with the Orange County portion within the City’s SOI. Visually, the hills frame and define Brea, and the homes, roads, and other infrastructure interface directly with these roughly 7,500 acres. Historically, oil production represented the predominant use in the hillside areas, with the County’s Olinda Alpha Landfill occupying many acres as well. During the 1980s and 1990s, the gradual depletion of oil resources in the hills led property owners to plan for alternative uses. Also, environmental interests and State park planners recognized that actions were required to stop increased loss of open space and valuable habitat throughout the Puente Hills and Chino Hills areas, and managed to secure many acres as permanent, protected open space use, such as Chino Hills State Park.” (2050 GPU page

35.)
This description omits any acknowledgement that industrial operations continue on Sycamore’s properties today and instead suggests that hillside oil operations were effectively depleted decades ago. This characterization also contradicts the 2050 GPU’s own admission that Sycamore’s properties are improved with active oil wells. (2050 GPU Figure PS-7, page 187.) The 2050 GPU also notes that the “community” has “long identified its desire to preserve the hillsides as undeveloped open space.” (2050 GPU page 46.) However, the 2050 GPU does not identify the source of this characterization of community sentiment, nor does it balance its claim with any discussion of the private property owner’s interest in the future of their lands.

The Draft PEIR’s hydrology analysis also characterizes the entire SOI area as “undeveloped”:
“The incorporated City of Brea is a largely developed suburban/urban community. The existing land use pattern is mixed and includes established residential neighborhoods, a concentrated downtown and mall/commercial core, industrial and business parks, civic and institutional uses, parks and open space, and transportation corridors. Most of the developed area is located west of Valencia Avenue, while the eastern portion consists primarily of residential neighborhoods, with large undeveloped foothills and canyons to the east and north. There is currently no development within the sphere of influence area, and only residential uses are permitted on approximately 34 percent of the total sphere of influence acreage under the current 2003 General Plan. The remaining 4,050 acres (66 percent) are designated for open space, parks/recreation, and public facilities, with no residential or non-residential development potential. Therefore, buildout of the Project area would largely come from redevelopment of already existing developed areas that contribute to urban storm water runoff.” (Draft PEIR page 4.9-28, emphasis added.)
“As described previously, the Project area is largely developed and buildout of the Project area would largely come from redevelopment of already existing developed areas City of Brea Planning Division
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(i.e., infill development). However, buildout would result in new development in previously undeveloped areas, primarily in the eastern portion of the City and its sphere of influence, which could result in an increase in storm water runoff quantities.

Redevelopment would also alter existing drainage of any given infill site that would affect the existing storm water drainage system.” (Draft PEIR page 4.9-32, emphasis added.)
This mischaracterization of Sycamore’s properties is carried over in the draft Public Safety Element:
“A significant portion of Brea’s sphere of influence (SOI) and surrounding area remains undeveloped and consists of rugged topography with highly flammable vegetation. The woodlands, grasslands, and chaparral areas provide important open space, natural resources, and scenic vistas, but also create fire hazards when development is located in or adjacent to these areas.” (2050 GPU page 168, emphasis added.) “Much of the SOI north of the City is sparsely developed and includes hillside residential areas, public facilities (such as the Olinda Alpha Landfill), parks and recreation areas, open space, and vacant parcels. These areas border the County of Los Angeles.” (Draft PEIR, page 2-12.)
The Draft PEIR provides the following breakdown of residential development capacity in the Hillside Residential area within the SOI:
“As shown in Table 2-1, there is currently no development within the SOI area, and only residential uses are permitted on approximately 34 percent of the total SOI acreage under the current 2003 Brea General Plan. The remaining 4,050 acres (66 percent) are designated for open space, parks/recreation, and public facilities, with no residential or non-residential development potential.” (Draft PEIR, page 2-13.) Table 2-1 (on page 2-11 of the Draft PEIR) allocates 2,096 acres to Hillside Residential, yielding 1,048 units and a maximum population of 2,987. The Draft PEIR does not include a breakdown of these calculations or describe the specific parcel-by-parcel methodology for these calculations. Without a transparent explanation of the assumptions underlying the SOI buildout analysis, it is difficult for the public or decisionmakers to understand how the Draft PEIR arrived at these development capacity figures or whether they accurately reflect the existing conditions and planning context of properties such as Sycamore’s properties. e. The Wildlife Corridor Analysis Is Insufficient and Internally Inconsistent As part of the proposed revisions in the 2050 GPU, the City has introduced a framework to address issues regarding wildlife corridors in the Planning Area. However, the 2050 GPU, Draft PEIR and its Biological Resources Technical Report (“BRTR”) contain material inconsistencies in the identification, depiction and analytical treatment of wildlife corridors, particularly within the SOI where Sycamore’s properties are located. These inconsistencies City of Brea Planning Division
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undermine the reliability of the biological baseline and compromise the Draft PEIR’s impact analysis under CEQA.

Figure CR-3 (Wildlife Corridor) in the 2050 GPU, based in part on mapping by Hills For Everyone, depicts an area with a “Connectivity Rank” of “Irreplaceable and Essential Corridors” over the Sycamore Property. (2050 GPU page 137, enclosed as Attachment 1.) The Community Resources Element explains that:
“The Puente and Chino Hills and Santa Ana Mountains together encompass about 511,000 acres of wildlands … Large blocks of habitat ridgelines along the Puente and Chino Hills allow wildlife to move throughout the hills and into the large open spaces of Chino Hills State Park and the Cleveland National Forest. Chino Hills State Park and the Puente and Whittier Hills are linked via the Tonner Canyon and Sonome Canyon wildlife corridors, illustrated in Figure CR-3.” (2050 GPU page 135.) However, the same geographic area is not identified as a wildlife corridor of any kind in Figure 9 (Wildlife Corridors/NCCPs) of the BRTR or Figure 4.3-5 of the Draft PEIR (enclosed as Attachment 2). Instead, Appendix E relies on the California Essential Habitat Connectivity Project (“CEHCP”) framework, depicting only “natural landscape blocks” and “small natural areas,” which apparently eliminates the entire swath of land shown in Figure CR-3. Though the BRTR includes discussion of “wildlife corridors and habitat linkages,” it only maps wildlife corridors. Further, the BRTR provides no additional context for the assignment of “Connectivity Ranks” as they are depicted in the 2050 GPU. The absence of the 2050 GPU-mapped corridor from the BRTR creates a direct inconsistency between the 2050 GPU and its technical baseline study that calls into question the basis for any of the “Connectivity Ranks” depicted in Figure CR-3.

In addition, several of the corridor depictions appear to extend beyond the City’s jurisdictional planning authority and across properties located outside the City’s boundaries or sphere of planning control. To the extent that these regional connectivity assumptions are intended to represent generalized ecological relationships rather than site-specific constraints, the 2050 GPU should clarify that such mapping is conceptual and not intended to function as a parcel-level constraint on future land use decisions. Without such clarification, the mapping may inadvertently imply the existence of a formally designated wildlife corridor where the Draft PEIR’s own technical analysis does not identify one.

The BRTR also contradicts itself by acknowledging the regional importance of the Puente-Chino Hills area as a movement corridor without providing supporting evidence from CEHCP:
“The Puente-Chino Hills area, located within and surrounding the northern and eastern portions of the Project area, provides connectivity between the Santa Ana mountains to the south and the San Gabriel mountains to the north, and function as a vital corridor for wildlife movement through the open space and native vegetation communities that occur in these areas.” (Draft PEIR Appendix E, page 26 and Draft PEIR page 4.3-37.) City of Brea Planning Division
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Despite this statement, the BRTR does not map this “vital corridor” in the same manner or extent as the 2050 GPU. The 2050 GPU treats this corridor as a policy-level wildlife corridor, while the BRTR treats connectivity more generally, without clearly identifying or mapping the same corridor. As a result, the biological baseline is internally inconsistent across documents.

The Draft PEIR relies on the BRTR as the technical foundation for its biological resources analysis. Section 4.3 of the Draft PEIR evaluates impacts related to wildlife corridors and habitat linkages using the BRTR’s mapping (in Draft PEIR Figure 4.3-5) and conclusions (including quoting directly from the BRTR as shown above):
“Biological resources documented as present or with potential to occur in the Proposed Project area were identified through a review of existing maps, literature and other biological studies conducted in the area, and sensitive species occurrence databases by the biological consultant. No biological survey, field reconnaissance, aquatic resources delineation, or focused species surveys were conducted as a part of the Proposed Project’s Biological Resources Technical Report (BRTR) (Appendix E of this Program Environmental Impact Report [PEIR]). The results of the review provide information on the potential constraints to project development due to the presence of sensitive biological resources. The potential presence of critical habitat in the Proposed Project area was also analyzed.” (Draft PEIR, page 4.3-10.)
“According to the California Essential Habitat Connectivity Project, which maps relatively natural habitat blocks that support native biodiversity, several areas spanning from northeast to southwest in the western portion of the Proposed Project area serve as natural landscape blocks (CDFW 2025e). Additionally, small natural areas are scattered throughout the Proposed Project area (Figure 4.3-5, Wildlife Corridors/NCCPs).” (Draft PEIR, page 4.3-37.)
“The Proposed Project area is likely to be used as a wildlife movement corridor because it provides suitable nesting, foraging, nursery, and dispersal areas for both sensitive and common wildlife species due to the presence of native vegetation communities and its connection and proximity to the Puente-Chino Hills area, the Pacific Coast, as well the [sic] Santa Ana mountains to the south and the San Gabriel mountains to the north.” (Draft PEIR, page 4.3-53.)
The Draft PEIR also acknowledges that the BRTR relied exclusively on existing literature, database searches, and prior studies and that no field reconnaissance, biological surveys, aquatic resource delineations, or focused species surveys were conducted for the Proposed Project area. (Draft PEIR, p. 4.3-10.) While the use of existing information may be appropriate at a programmatic level in certain circumstances, CEQA requires that an EIR describe the physical environmental conditions in the vicinity of the project with sufficient accuracy to establish a meaningful baseline for impact analysis. (See CEQA Guidelines § 15125.) Where environmental constraints such as wildlife movement corridors, habitat linkages, or sensitive biological resources are relied upon as a basis for policy decisions or development City of Brea Planning Division
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constraints, the supporting analysis should be grounded in reasonably current and site-specific information.

Here, the absence of any field verification creates additional uncertainty regarding the biological conditions of lands within the SOI, including Sycamore’s properties. The Draft PEIR simultaneously asserts the existence of wildlife movement corridors and sensitive habitat connectivity while acknowledging that no on-site surveys were conducted to confirm the presence, location, or functional characteristics of those resources. This analytical gap is particularly significant given the internal inconsistencies between the 2050 GPU mapping and the BRTR corridor analysis discussed above. Without field-verified baseline information, the Draft PEIR’s conclusions regarding wildlife movement patterns and habitat connectivity within the Planning Area remain uncertain and may not provide a reliable foundation for long-term land use policy decisions reflected in the 2050 GPU.

Accordingly, the Final PEIR should clarify the methodology used to characterize biological resources within the SOI and explain the basis for the corridor designations depicted in the 2050 GPU. To the extent that those designations rely on generalized regional data rather than site-specific conditions, the Final PEIR should expressly acknowledge those limitations so that future project-level environmental review can rely on updated biological surveys and more precise analysis.

Because the Draft PEIR and the 2050 GPU present inconsistent maps defining wildlife corridors, the Draft PEIR’s impact analysis may fail to analyze impacts to a corridor that the 2050 GPU itself designates. Absent any reconciliation of these discrepancies, the Draft PEIR may not fully analyze impacts to all wildlife corridors and habitat linkages contemplated by the proposed policy framework. As this inconsistency has direct implications for Sycamore’s properties, we urge the City to fully and properly analyze these potential impacts taking into account a complete and accurate characterization of the condition of the CA-57 North Property and the Carbon Canyon Property, inclusive of the Olinda Drive Property.

III. Conclusion
Sycamore asks that the City thoughtfully consider and implement revisions to the 2050 GPU that facilitate the use of a future specific plan framework for the CA-57 North Property and Carbon Canyon Property, inclusive of the Olinda Drive Property. Sycamore also asks that the City correct the 2050 GPU and Draft PEIR errors and deficiencies identified above. Please do not hesitate to contact me by email at [email protected] or my colleague Noah Adler ([email protected]) with any questions.

Sincerely,

MANATT, PHELPS & PHILLIPS, LLP
on behalf of Sycamore Development Brea Canyon LLC
Enclosures: Attachments 1-2
cc: George Basye, Sycamore Development Partners
ATTACHMENT 1

ATTACHMENT 2

AFFILIATED AGENCIES

Orange County
Transit District
Local Transportation
Authority
Service Authority for
Freeway Emergencies
Consolidated
Transportation
Service Agency
Congestion Management
Agency

Orange County Transportation Authority
550 South Main Street / P.O Box 14184 / Orange / California 92863-1584 / (714) 560-OCTA (6282) March 26, 2026
Planning Division
Community Development Department
City of Brea
1 Civic Center Circle
Brea, CA 92821
Via email: [email protected]
Subject: Brea 2050: Focused General Plan Update and Brea Core Specific Plan Draft Program Environmental Impact Report (SCH No. 2025081123)
To Whom It May Concern:

Thank you for providing the Orange County Transportation Authority (OCTA) with the opportunity to review the Draft Program Environmental Impact Report (PEIR) for the City of Brea’s Brea 2050: Focused General Plan Update and Brea Core Specific Plan (SCH No. 2025081123). The following comments regarding the Draft PEIR Appendix H (“Transportation Impact Analysis”), Section 3 (“Existing Conditions”) are provided for your consideration:
• On page 8, under “Transit Service,” the document currently states, “It [OCTA] provides approximately 60 fixed bus routes, including local, community, express (Bravo!), and StationLink services on a countywide basis.” Please revise this to, “51 fixed bus routes, including local, community, rapid, and StationLink services,” to reflect recent service updates and branding changes.
• On page 9, please update Table 1: Transit Service in Brea to reflect recent OC Bus service changes:
• Route 59 now operates between the cities of Brea and Irvine. • Route 129 now operates between the cities of Brea and Buena Park.
• On page 10, please revise Figure 1: Existing Transit Service in Brea to reflect recent changes to OC Bus Route 129. This route now terminates at Brea Mall and no longer operates on Birch Street or Kraemer Boulevard.

Planning Division
Community Development Department
March 26, 2026

Page 2 ends

Orange County Transportation Authority
550 South Main Street / P.O Box 14184 / Orange / California 92863-1584 / (714) 560-OCTA (6282) Thank you for the opportunity to review this document. Should you have any questions or comments, please contact me at (714) 560-5907 or at [email protected].

Sincerely,
Dan Phu
Director, Transportation Planning and Analysis
DP:pv

700 North Alameda Street, Los Angeles, California 90012⚫ Mailing Address: Box 54153, Los Angeles⚫California 90054-0153 ⚫ Telephone (213) 217-6000 March 17, 2026 VIA EMAIL
City of Brea
Planning Division
1 Civic Center Circle
Brea, CA 92821
[email protected]
To Whom It May Concern:

Draft Program Environmental Impact Report for the
Brea 2050: Focused General Plan Update and Brea Core Specific Plan Project The Metropolitan Water District of Southern California (Metropolitan) has reviewed the Notice of Availability and Draft Program Environmental Impact Report for the Brea 2050: Focused General Plan Update and Brea Core Specific Plan Project. The Project proposes to adopt and implement the Focused General Plan Update (GPU), which includes comprehensive updates to the City’s 2003 Brea General Plan Community Development, Community Resources, and Public Safety elements.

The Focused GPU also includes new Mobility and Economic Development elements. The purpose of the Focused GPU is to ensure that General Plan policies and programs align with current community needs, state mandates, and planning principles per the 2023 General Audit. In addition, the project consists of the Brea Core Specific Plan (BCSP), which aims to implement the values of the 2017 Brea Envisions Community Strategic Plan and the goals, policies, and recommendations of the 2020 Brea Connecting the Core Active Transportation Plan. The BCSP establishes land uses, provides mobility recommendations and streetscape improvements, proposes infrastructure upgrades to support new development, and outlines implementation strategies.

Metropolitan owns and operates facilities within and adjacent to the proposed Project Limits. As shown on the attached map, Metropolitan’s Lower Feeder, Orange County Feeder, and Yorba Linda Feeder are within the Project boundary. Lower Feeder is an approximately 96-inch inside-diameter pipeline extending east/west through Brea, primarily along Lambert Road within street easement right-of-way. Orange County Feeder is an approximately 36-inch inside diameter pipeline extending north/south along S. Randolph Ave. and E. Birch St. within street easement right of way. Yorba Linda Feeder is an approximately 96-inch inside-diameter pipeline extending north/south across Carbon Canyon Road. Metropolitan is concerned with potential impacts to these facilities and rights-of-way that may result from implementation of the proposed Project.

Metropolitan must be allowed to maintain its rights-of-way and access to its facilities and properties at all times, in order to repair and maintain the current condition of those facilities. In order to avoid potential conflicts with Metropolitan's rights-of-way, we require that any design plans for any activity in the area of Metropolitan's pipelines or facilities be submitted for our review and written Docusign Envelope ID: FC83EA4B-94DE-46CF-AA93-BAEF385EEAF2

THE METROPOLITAN WATER DISTRICT OF SOUTHERN CALIFORNIA
City of Brea

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March 17, 2026
approval. Metropolitan will not permit procedures that could subject the pipes to excessive vehicle, impact, or vibratory loads. Any future design plans associated with this Project should be submitted to the attention of Metropolitan's Substructures Team. Approval of the Project should be contingent on Metropolitan's approval of design plans for portions of the proposed Project that could impact its facilities.

Metropolitan requests that the City of Brea avoid any potential impacts that may occur to Lower Feeder, Orange County Feeder, and Yorba Linda Feeder due to implementation of the proposed Project, or, where applicable, and propose mitigation measures to offset any potential impacts. It will also be necessary for the City of Brea to consider Metropolitan’s Lower Feeder, Orange County Feeder, and Yorba Linda Feeder in its project planning.

Detailed prints of drawings of Metropolitan's pipelines and rights-of-way may be obtained by contacting Metropolitan's Substructures Team at [email protected]. To assist the City of Brea in preparing plans that are compatible with Metropolitan's facilities and rights-of-way, enclosed is a copy of the "Guidelines for Developments in the Area of Facilities, Fee Properties, and/or Easement of The Metropolitan Water District of Southern California." Please note that Metropolitan's facilities and rights-of-way must be fully shown and identified as Metropolitan's on all designs or plans submitted.

Metropolitan provides the following additional specific comment on the DEIR for the Brea 2050 Focused General Plan Update and Brea Core Specific Plan Project:

1. Pages 4.15-23 and 4.15-37 state that the City’s public water system receives imported water from the California Domestic Water Company and the Metropolitan Water District of Orange County. Please correct Metropolitan Water District of Orange County to Municipal Water District of Orange County.

We appreciate the opportunity to provide input to your planning process and look forward to receiving future plans and documentation for this Project. If we can be of further assistance, please contact Jolene Ditmar at (213) 217- 6184 or at [email protected].

Very truly yours,
Sean Carlson
Team Manager, Environmental Planning Section
JD:cs
s:\externalreviews\externalreviews\commentletters\2026-commentletters\brea_2050focusedgpupdate&corespecificplan_noa Enclosures (2)
Docusign Envelope ID: FC83EA4B-94DE-46CF-AA93-BAEF385EEAF2

Additional Copies: To obtain a copy of this document, please contact the Engineering Services Group, Substructures Team.

Disclaimer
Metropolitan assumes no responsibility for the accuracy of the substructure information herein provided.

The user assumes responsibility for verifying substructure locations before excavating and assumes all liability for damage to Metropolitan’s facilities as a result of such excavation. Additionally, the user is cautioned to conduct surveys and other field investigations as deemed prudent, to assure that project plans are correct. The appropriate representative from Metropolitan must be contacted at least two working days, before any work activity in proximity to Metropolitan’s facilities.

It generally takes 30 days to review project plans and provide written responses. Metropolitan reserves the right to modify requirements based on case-specific issues and regulatory developments.

PUBLICATION HISTORY:

Initial Release July 2018
Docusign Envelope ID: FC83EA4B-94DE-46CF-AA93-BAEF385EEAF2 The Metropolitan Water District of Southern California IMPROVEMENTS AND CONSTRUCTION GUIDELINES Table of Contents
Issue Date: July 2018

1.0 GENERAL INFORMATION ............................................................................................. 1

1.1 Introduction.................................................................................................................. 1

1.2 Submittal and Review of Project Plans/Utilities and Maps............................................ 1

1.3 Identification of Metropolitan’s Facilities and Rights-of-Way......................................... 3

2.0 General Requirements .................................................................................................... 3

2.1 Vehicular Access ......................................................................................................... 3

2.2 Fences......................................................................................................................... 3

2.3 Driveways and Ramps ................................................................................................. 3

2.4 Walks, Bike Paths, and Trails ...................................................................................... 3

2.5 Clear Zones ................................................................................................................. 4

2.6 Slopes.......................................................................................................................... 4

2.7 Structures .................................................................................................................... 4

2.8 Protection of Metropolitan Facilities ............................................................................. 4

2.9 Potholing of Metropolitan Pipelines .............................................................................. 4

2.10 Jacked Casings or Tunnels.......................................................................................... 4

3.0 Landscaping.................................................................................................................... 5

3.1 Plans............................................................................................................................ 5

3.2 Drought-Tolerant Native and California Friendly Plants................................................ 5

3.3 Trees ........................................................................................................................... 5

3.4 Other Vegetation.......................................................................................................... 6

3.5 Irrigation....................................................................................................................... 6

3.6 Metropolitan Vehicular Access..................................................................................... 6

4.0 General Utilities ............................................................................................................... 6

4.1 Utility Structures........................................................................................................... 6

4.2 Utility Crossings ........................................................................................................... 6

4.3 Longitudinal Utilities..................................................................................................... 7

4.4 Underground Electrical Lines ....................................................................................... 7

4.5 Fiber Optic Lines.......................................................................................................... 7

4.6 Overhead Electrical and Telephone Lines.................................................................... 7

4.7 Sewage Disposal Systems........................................................................................... 7

4.8 Underground Tanks ..................................................................................................... 8

5.0 Specific Utilities: Non-Potable Utility Pipelines................................................................. 8

6.0 Cathodic Protection/Electrolysis Test Stations................................................................. 8

6.1 Metropolitan Cathodic Protection ................................................................................. 8

6.2 Review of Cathodic Protection Systems....................................................................... 8

7.0 Drainage.......................................................................................................................... 9

7.1 Drainage Changes Affecting Metropolitan Rights-of-Way............................................. 9

7.2 Metropolitan’s Blowoff and Pumpwell Structures.......................................................... 9

8.0 Grading and Settlement................................................................................................... 9 Docusign Envelope ID: FC83EA4B-94DE-46CF-AA93-BAEF385EEAF2 The Metropolitan Water District of Southern California IMPROVEMENTS AND CONSTRUCTION GUIDELINES Table of Contents
Issue Date: July 2018

8.1 Changes in Cover over Metropolitan Pipelines............................................................. 9

8.2 Settlement ................................................................................................................... 9

9.0 Construction Equipment .................................................................................................10

9.1 Review of Proposed Equipment..................................................................................10

9.2 Equipment Restrictions ...............................................................................................10

9.3 Vibratory Compaction Equipment................................................................................10

9.4 Equipment Descriptions ..............................................................................................10

10.0 Excavations Close to Metropolitan Facilities...................................................................11

10.1 Shoring Design Submittal............................................................................................11

10.2 Shoring Design Requirements ....................................................................................11

11.0 Support of Metropolitan Facilities....................................................................................11

11.1 Support Design Submittal ...........................................................................................11

11.2 Support Design Requirements ....................................................................................11

12.0 Backfill............................................................................................................................12

12.1 Metropolitan Pipeline Not Supported...........................................................................12

12.2 Metropolitan Pipeline Partially Exposed ......................................................................12

12.3 Metropolitan Cut and Cover Conduit on Colorado River Aqueduct (CRA)...................12

13.0 Piles ...............................................................................................................................13

13.1 Impacts on Metropolitan Pipelines ..............................................................................13

13.2 Permanent Cast-in-place Piles....................................................................................13

14.0 Protective Slabs for Road Crossings Over Metropolitan Pipelines ..................................13

15.0 Blasting ..........................................................................................................................13

16.0 Metropolitan Plan Review Costs, Construction Costs and Billing....................................14

16.1 Plan Review Costs......................................................................................................14

16.2 Cost of Modification of Facilities Performed by Metropolitan .......................................14

16.3 Final Billing .................................................................................................................14

17.0 Street Vacations and Reservation of Easements for Metropolitan ..................................14

18.0 Metropolitan Land Use Guidelines..................................................................................14

19.0 Compliance with Environmental Laws and Regulations..................................................15

20.0 Paramount Rights / Metropolitan’s Rights within Existing Rights-of-Way ........................17

21.0 Disclaimer and Information Accuracy .............................................................................17 Docusign Envelope ID: FC83EA4B-94DE-46CF-AA93-BAEF385EEAF2 The Metropolitan Water District of Southern California IMPROVEMENTS AND CONSTRUCTION GUIDELINES Table of Contents
Issue Date: July 2018
Table 1: General Guidelines for Pipeline Separation between Metropolitan’s Pipeline1 and Sanitary Sewer2 or Hazardous Fluid Pipeline3
...........................................................18 Table 2: General Guidelines for Pipeline “Separation between Metropolitan’s Pipeline1 and Storm Drain and/or Recycled Water2 ........................................................................19 Table 3: General Guidelines for Pipeline “Separation1 between Metropolitan’s Pipeline and Recycled Water2,4 Irrigationsm,.................................................................................20 Figure 1: AASHTO H-20 Loading..............................................................................................21 Figure 2: Drawing SK-1 .............................................................................................................22 Docusign Envelope ID: FC83EA4B-94DE-46CF-AA93-BAEF385EEAF2 The Metropolitan Water District of Southern California IMPROVEMENTS AND CONSTRUCTION GUIDELINES Issue Date: July 2018
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Docusign Envelope ID: FC83EA4B-94DE-46CF-AA93-BAEF385EEAF2 The Metropolitan Water District of Southern California IMPROVEMENTS AND CONSTRUCTION GUIDELINES Issue Date: July 2018 Page 1 of 22

1.0 GENERAL INFORMATION
Note: Underground Service Alert at 811 must be notified at least two working days before excavating in proximity to Metropolitan’s facilities.

1.1 Introduction
These guidelines provide minimum design and construction requirements for any utilities, facilities, developments, and improvements, or any other projects or activities, proposed in or near Metropolitan Water District of Southern California (Metropolitan) facilities and rights-of-way. Additional conditions and stipulations may also be required depending on project and site specific conditions. Any adverse impacts to Metropolitan’s conveyance system, as determined by Metropolitan, will need to be mitigated to its satisfaction.

All improvements and activities must be designed so as to allow for removal or relocation at builder or developer expense, as set forth in the paramount rights provisions of Section 20.0. Metropolitan shall not be responsible for repair or replacement of improvements, landscaping or vegetation in the event Metropolitan exercises its paramount rights powers.

1.2 Submittal and Review of Project Plans/Utilities and Maps Metropolitan requires project plans/utilities be submitted for all proposed activities that may impact Metropolitan’s facilities or rights-of-way. Project plans shall include copies of all pertinent utilities, sewer line, storm drain, street improvement, grading, site development, landscaping, irrigation and other plans, all tract and parcel maps, and all necessary state and federal environmental documentation. Metropolitan will review the project plans and provide written approval, as it pertains to Metropolitan’s facilities and rights-of-way. Written approval from Metropolitan must be obtained, prior to the start of any activity or construction in the area of Metropolitan’s facilities or rights-of-way. Once complete project plans and supporting documents are submitted to Metropolitan, it generally takes 30 days to review and to prepare a detailed written response. Complex engineering plans that have the potential for significant impacts on Metropolitan’s facilities or rights-of-way may require a longer review time.

Project plans, maps, or any other information should be submitted to Metropolitan’s Substructures Team at the following mailing address:

Attn: Substructures Team
The Metropolitan Water District of Southern California
700 North Alameda St.

Los Angeles, CA 90012
General Mailing Address: P.O. Box 54153
Los Angeles, CA 90054-0153
Email: [email protected]
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For additional information, or to request prints of detailed drawings for Metropolitan’s facilities and rights-of-way, please contact Metropolitan’s Substructures Team at 213- 217-7663 or [email protected].

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1.3 Identification of Metropolitan’s Facilities and Rights-of-Way Metropolitan’s facilities and rights-of-way must be fully shown and identified as Metropolitan’s, with official recording data, on the following:

A. All applicable plans
B. All applicable tract and parcel maps
Metropolitan’s rights-of-ways and existing survey monuments must be tied dimensionally to the tract or parcel boundaries. Metropolitan’s Records of Survey must be referenced on the tract and parcel maps with the appropriate Book and Page.

2.0 General Requirements

2.1 Vehicular Access
Metropolitan must have vehicular access along its rights-of-way at all times for routine inspection, patrolling, operations, and maintenance of its facilities and construction activities. All proposed improvements and activities must be designed so as to accommodate such vehicular access.

2.2 Fences
Fences installed across Metropolitan’s rights-of-way must include a 16-foot-wide gate to accommodate vehicular access by Metropolitan. Additionally, gates may be required at other specified locations to prevent unauthorized entry into Metropolitan’s rights-of-way.

All gates must accommodate a Metropolitan lock or Knox-Box with override switch to allow Metropolitan unrestricted access. There should be a minimum 20-foot setback for gates from the street at the driveway approach. The setback is necessary to allow Metropolitan vehicles to safely pull off the road prior to opening the gate.

2.3 Driveways and Ramps
Construction of 16-foot-wide commercial-type driveway approaches is required on both sides of all streets that cross Metropolitan’s rights-of-way. Access ramps, if necessary, must be a minimum of 16 feet wide.

There should be a minimum 20-foot setback for gates from the street at the driveway approach. Grades of ramps and access roads must not exceed 10 percent; if the slope of an access ramp or road must exceed 10 percent due to topography, then the ramp or road must be paved.

2.4 Walks, Bike Paths, and Trails
All walkways, bike paths, and trails along Metropolitan’s rights-of-way must be a minimum 12-foot wide and have a 50-foot or greater radius on all horizontal curves if also used as Metropolitan’s access roads. Metropolitan’s access routes, including all walks and drainage facilities crossing the access routes, must be constructed to American Association of State Highway and Transportation Officials (AASHTO) H-20 loading standards (see Figure 1). Additional requirements will be placed on equestrian trails to protect the water quality of Metropolitan’s pipelines and facilities.

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2.5 Clear Zones
A 20-foot-wide clear zone is required to be maintained around Metropolitan’s manholes and other above-ground facilities to accommodate vehicular access and maintenance.

The clear zone should slope away from Metropolitan’s facilities on a grade not to exceed 2 percent.

2.6 Slopes
Cut or fill slopes proposed within Metropolitan’s rights-of-way must not exceed 10 percent. The proposed grade must not worsen the existing condition. This restriction is required to facilitate Metropolitan use of construction and maintenance equipment and allow uninhibited access to above-ground and below-ground facilities.

2.7 Structures
Construction of structures of any type is not allowed within the limits of Metropolitan’s rights-of-way to avoid interference with the operation and maintenance of Metropolitan’s facilities and possible construction of future facilities.

Footings and roof eaves of any proposed buildings adjacent to Metropolitan’s rights-ofway must meet the following criteria:

A. Footings and roof eaves must not encroach onto Metropolitan’s rights-of-way.

B. Footings must not impose any additional loading on Metropolitan’s facilities.

C. Roof eaves must not overhang onto Metropolitan’s rights-of-way.

Detailed plans of footings and roof eaves adjacent to Metropolitan’s rights-of-way must be submitted for Metropolitan’s review and written approval, as pertains to Metropolitan’s facilities.

2.8 Protection of Metropolitan Facilities
Metropolitan facilities within its rights-of-way, including pipelines, structures, manholes, survey monuments, etc., must be protected from damage by the project proponent or property owner, at no expense to Metropolitan. The exact location, description and method of protection must be shown on the project plans.

2.9 Potholing of Metropolitan Pipelines
Metropolitan’s pipelines must be potholed in advance, if the vertical clearance between a proposed utility and Metropolitan’s pipeline is indicated to be 4 feet or less. A Metropolitan representative must be present during the potholing operation and will assist in locating the pipeline. Notice is required, a minimum of three working days, prior to any potholing activity.

2.10 Jacked Casings or Tunnels
A. General Requirements
Utility crossings installed by jacking, or in a jacked casing or tunnel under/over a Metropolitan pipeline, must have at least 3 feet of vertical clearance between the outside diameter of the pipelines and the jacked pipe, casing, or tunnel. The actual Docusign Envelope ID: FC83EA4B-94DE-46CF-AA93-BAEF385EEAF2 The Metropolitan Water District of Southern California IMPROVEMENTS AND CONSTRUCTION GUIDELINES Issue Date: July 2018 Page 5 of 22
cover over Metropolitan’s pipeline shall be determined by potholing, under Metropolitan’s supervision.

Utilities installed in a jacked casing or tunnel must have the annular space between the utility and the jacked casing or tunnel filled with grout. Provisions must be made for grouting any voids around the exterior of the jacked pipe, casing, or tunnel.

B. Jacking or Tunneling Procedures
Detailed jacking, tunneling, or directional boring procedures must be submitted to Metropolitan for review and approval. The procedures must cover all aspects of operation, including, but not limited to, dewatering, ground control, alignment control, and grouting pressure. The submittal must also include procedures to be used to control sloughing, running, or wet ground, if encountered. A minimum 10-foot clearance must be maintained between the face of the tunneling or receiving pits and outside edges of Metropolitan’s facility.

C. Shoring
Detailed drawings of shoring for jacking or receiving pits must be submitted to Metropolitan for review and written-approval. (See Section 10 for shoring requirements).

D. Temporary Support
Temporary support of Metropolitan’s pipelines may be required when a utility crosses under a Metropolitan pipeline and is installed by means of an open trench. Plans for temporary support must be reviewed and approved in writing by Metropolitan. (See Section 11, Supports of Metropolitan Facilities).

3.0 Landscaping

3.1 Plans
All landscape plans must show the location and limits of Metropolitan’s right-of-way and the location and size of Metropolitan’s pipeline and related facilities therein. All landscaping and vegetation shall be subject to removal without notice, as may be required by Metropolitan for ongoing maintenance, access, repair, and construction activities. Metropolitan will not be financially responsible for the removal of any landscaping and vegetation.

3.2 Drought-Tolerant Native and California Friendly Plants Metropolitan recommends use of drought-tolerant native and California Friendly® plants (excluding sensitive plants) on proposed projects. For more information regarding California Friendly® plants refer to www.bewaterwise.com.

3.3 Trees
Trees are generally prohibited within Metropolitan’s rights-of-way as they restrict Metropolitan’s ability to operate, maintain and/or install new pipeline(s) located within these rights-of-way. Metropolitan will not be financially responsible for the removal and replacement of any existing trees should they interfere with access and any current or future Metropolitan project located within the right-of-way.

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3.4 Other Vegetation
Shrubs, bushes, vines, and groundcover are generally allowed within Metropolitan’s rights-of-way. Larger shrubs are not allowed on Metropolitan fee properties; however, they may be allowed within its easements if planted no closer than 15 feet from the outside edges of existing or future Metropolitan facilities. Only groundcover is allowed to be planted directly over Metropolitan pipeline, turf blocks or similar is recommended to accommodate our utility vehicle access. Metropolitan will not be financially responsible for the removal and replacement of the vegetation should it interfere with access and any current or future Metropolitan project.

3.5 Irrigation
Irrigation systems are acceptable within Metropolitan’s rights-of-way, provided valves and controllers are located near the edges of the right-of-way and do not interfere with Metropolitan vehicular access. A shutoff valve should also be located along the edge of the right-of-way that will allow the shutdown of the system within the right-of-way should Metropolitan need to do any excavation. No pooling or saturation of water above Metropolitan’s pipeline and right-of-way is allowed. Additional restrictions apply to nonpotable water such as Recycled Water and are covered on Table 3 of Page 20.

3.6 Metropolitan Vehicular Access
Landscape plans must show Metropolitan vehicular access to Metropolitan’s facilities and rights-of-way and must be maintained by the property owner or manager or homeowners association at all times. Walkways, bike paths, and trails within Metropolitan’s rights-of-way may be used as Metropolitan access routes. (See Section

2.4, Walks, Bike Paths, and Trails).

4.0 General Utilities
Note: For non-potable piping like sewer, hazardous fluid, storm drain, disinfected tertiary recycled water and recycled water irrigation see Table 1 through Table 3.

4.1 Utility Structures
Permanent utility structures (e.g., manholes, power poles, pull boxes, electrical vaults, etc.) are not allowed within Metropolitan’s rights-of-way. Metropolitan requests that all permanent utility structures within public streets be placed as far from its pipelines and facilities as practical, but not closer than 5 feet from the outside edges of Metropolitan facilities.

Note: Non-potable utility pipelines are an exception to the 5-foot minimum clearance.

Non-potable utility pipelines should have 10 feet of separation.

4.2 Utility Crossings
Metropolitan requests a minimum of 1 foot of vertical clearance between Metropolitan’s pipeline and any utility crossing the pipeline. Utility lines crossing Metropolitan’s pipelines must be as perpendicular to the pipeline as possible. Cross-section drawings, showing proposed locations and elevations of utility lines and locations of Metropolitan’s pipelines and limits of rights-of-way, must be submitted with utility plans, for all Docusign Envelope ID: FC83EA4B-94DE-46CF-AA93-BAEF385EEAF2 The Metropolitan Water District of Southern California IMPROVEMENTS AND CONSTRUCTION GUIDELINES Issue Date: July 2018 Page 7 of 22
crossings. Metropolitan’s pipeline must be potholed under Metropolitan’s supervision at the crossings (See Section 2.9).

4.3 Longitudinal Utilities
Installation of longitudinal utilities is generally not allowed along Metropolitan’s rights-ofway. Within public streets, Metropolitan requests that all utilities parallel to Metropolitan’s pipelines and appurtenant structures (facilities) be located as far from the facilities as possible, with a minimum clearance of 5 feet from the outside edges of the pipeline.

Note: Non-potable utility pipelines are an exception to the 5-foot minimum clearance.

Non-potable utility pipelines should have 10 feet of separation (for more information See Table 1 on Page 18).

4.4 Underground Electrical Lines
Underground electrical conduits (110 volts or greater) which cross a Metropolitan’s pipeline must have a minimum of 1 foot of vertical clearance between Metropolitan’s pipeline and the electrical lines. Longitudinal electrical lines, including pull boxes and vaults, in public streets should have a minimum separation of 5 feet from the edge of a Metropolitan pipeline or structures.

4.5 Fiber Optic Lines
Fiber optic lines installed by directional boring require a minimum of 3 feet of vertical clearance when boring is over Metropolitan’s pipelines and a minimum of 5 feet of vertical clearance when boring is under Metropolitan’s pipelines. Longitudinal fiber optic lines, including pull boxes, in public streets should have a minimum separation of 5 feet from the edge of a Metropolitan pipelines or structures. Potholing must be performed, under Metropolitan’s supervision, to verify the vertical clearances are maintained.

4.6 Overhead Electrical and Telephone Lines
Overhead electrical and telephone lines, where they cross Metropolitan’s rights-of-way, must have a minimum 35 feet of clearance, as measured from the ground to the lowest point of the overhead line. Overhead electrical lines poles must be located at least 30 feet laterally from the edges of Metropolitan’s facilities or outside Metropolitan’s rightof-way, whichever is greater.

Longitudinal overhead electrical and or telephone lines in public streets should have a minimum separation of 10 feet from the edge of a Metropolitan pipelines or structures where possible.

4.7 Sewage Disposal Systems
Sewage disposal systems, including leach lines and septic tanks, must be a minimum of 100 feet from the outside limits of Metropolitan’s rights-of-way or the edge of its facilities, whichever is greater. If soil conditions are poor, or other adverse site-specific conditions exist, a minimum distance of 150 feet is required. They must also comply with local and state health code requirements as they relate to sewage disposal systems in proximity to major drinking water supply pipelines.

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4.8 Underground Tanks
Underground tanks containing hazardous materials must be a minimum of 100 feet from the outside limits of Metropolitan’s rights-of-way or edge of its facilities, whichever is greater. In addition, groundwater flow should be considered with the placement of underground tanks down-gradient of Metropolitan’s facilities.

5.0 Specific Utilities: Non-Potable Utility Pipelines
In addition to Metropolitan’s general requirements, installation of non-potable utility pipelines (e.g., storm drains, sewers, and hazardous fluids pipelines) in Metropolitan's rights-of-way and public street rights-of-way must also conform to the State Water Resources Control Board’s Division of Drinking Water (DDW) regulation (Waterworks Standards) and guidance for separation of water mains and non-potable pipelines and to applicable local county health code requirements. Written approval is required from DDW for the implementation of alternatives to the Waterworks Standards and, effective December 14, 2017, requests for alternatives to the Waterworks Standards must include information consistent with: DDW’s Waterworks Standards Main Separation Alternative Request Checklist.

In addition to the following general guidelines, further review of the proposed project must be evaluated by Metropolitan and requirements may vary based on site specific conditions.

A. Sanitary Sewer and Hazardous Fluids (General Guideline See Table 1 on Page 18) B. Storm Drain and Recycled Water (General Guideline See Table 2 on Page 19) C. Irrigation with Recycled Water (General Guideline See Table 3 on Page 20) D. Metropolitan generally does not allow Irrigation with recycled water to be applied directly above its treated water pipelines
E. Metropolitan requests copies of project correspondence with regulating agencies (e.g., Regional Water Quality Control Board, DDW); regarding the application of recycled water for all projects located on Metropolitan’s rights-of-way

6.0 Cathodic Protection/Electrolysis Test Stations

6.1 Metropolitan Cathodic Protection
Metropolitan’s existing cathodic protection facilities in the vicinity of any proposed work must be identified prior to any grading or excavation. The exact location, description, and type of protection must be shown on all project plans. Please contact Metropolitan for the location of its cathodic protection stations.

6.2 Review of Cathodic Protection Systems
Metropolitan must review any proposed installation of impressed-current cathodic protection systems on pipelines crossing or paralleling Metropolitan’s pipelines to determine any potential conflicts with Metropolitan’s existing cathodic protection system.

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7.0 Drainage

7.1 Drainage Changes Affecting Metropolitan Rights-of-Way Changes to existing drainage that could affect Metropolitan’s rights-of-way require Metropolitan’s approval. The project proponent must provide acceptable solutions to ensure Metropolitan’s rights-of-way are not negatively affected by changes in the drainage conditions. Plans showing the changes, with a copy of a supporting hydrology report and hydraulic calculations, must be submitted to Metropolitan for review and approval. Long term maintenance of any proposed drainage facilities must be the responsibility of the project proponent, City, County, homeowner’s association, etc., with a clear understanding of where this responsibility lies. If drainage must be discharged across Metropolitan’s rights-of-way, it must be carried across by closed conduit or lined open channel and must be shown on the plans.

7.2 Metropolitan’s Blowoff and Pumpwell Structures
Any changes to the existing local watercourse systems will need to be designed to accommodate Metropolitan’s blowoff and pumpwell structures, which periodically convey discharged water from Metropolitan’s blowoff and pumping well structures during pipeline dewatering. The project proponents’ plans should include details of how these discharges are accommodated within the proposed development and must be submitted to Metropolitan for review and approval. Any blowoff discharge lines impacted must be modified accordingly at the expense of the project proponent.

8.0 Grading and Settlement

8.1 Changes in Cover over Metropolitan Pipelines
The existing cover over Metropolitan’s pipelines must be maintained unless Metropolitan determines that proposed changes in grade and cover do not pose a hazard to the integrity of the pipeline or an impediment to its maintenance capability. Load and settlement or rebound due to change in cover over a Metropolitan pipeline or ground in the area of Metropolitan’s rights-of-way will be factors considered by Metropolitan during project review.

In general, the minimum cover over a Metropolitan pipeline is 4 feet and the maximum cover varies per different pipeline. Any changes to the existing grade may require that Metropolitan’s pipeline be potholed under Metropolitan’s supervision to verify the existing cover.

8.2 Settlement
Any changes to the existing topography in the area of Metropolitan’s pipeline or right-ofway that result in significant settlement or lateral displacement of Metropolitan’s pipelines are not acceptable. Metropolitan may require submittal of a soils report showing the predicted settlement of the pipeline at 10-foot intervals for review. The data must be carried past the point of zero change in each direction and the actual size and varying depth of the fill must be considered when determining the settlement. Possible settlement due to soil collapse, rebound and lateral displacement must also be included.

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In general, the typical maximum allowed deflection for Metropolitan’s pipelines must not exceed a deflection of 1/4-inch for every 100 feet of pipe length. Metropolitan may require additional information per its Geotechnical Guidelines. Please contact Metropolitan’s Substructures Team for a copy of the Geotechnical Guidelines.

9.0 Construction Equipment

9.1 Review of Proposed Equipment
Use of equipment across or adjacent to Metropolitan’s facilities is subject to prior review and written approval by Metropolitan. Excavation, backfill, and other work in the vicinity of Metropolitan’s facilities must be performed only by methods and with equipment approved by Metropolitan. A list of all equipment to be used must be submitted to Metropolitan a minimum of 30 days before the start of work.

A. For equipment operating within paved public roadways, equipment that imposes loads not greater than that of an AASHTO H-20 vehicle (see Figure 1 on Page 21) may operate across or adjacent to Metropolitan’s pipelines provided the equipment operates in non-vibratory mode and the road remains continuously paved.

B. For equipment operating within unpaved public roadways, when the total cover over Metropolitan’s pipeline is 10 feet or greater, equipment imposing loads no greater than those imposed by an AASHTO H-20 vehicle may operate over or adjacent to the pipeline provided the equipment is operated in non-vibratory mode. For crossings, vehicle path shall be maintained in a smooth condition, with no breaks in grade for 3 vehicle lengths on each side of the pipeline.

9.2 Equipment Restrictions
In general, no equipment may be used closer than 20 feet from all Metropolitan aboveground structures. The area around the structures should be flagged to prevent equipment encroaching into this zone.

9.3 Vibratory Compaction Equipment
Vibratory compaction equipment may not be used in vibratory mode within 20 feet of the edge of Metropolitan’s pipelines.

9.4 Equipment Descriptions
The following information/specifications for each piece of equipment should be included on the list:

A. A description of the equipment, including the type, manufacturer, model year, and model number. For example, wheel tractor-scraper, 1990 Caterpillar 627E.

B. The empty and loaded total weight and the corresponding weight distribution. If equipment will be used empty only, it should be clearly stated.

C. The wheel base (for each axle), tread width (for each axle), and tire footprint (width and length) or the track ground contact (width and length), and track gauge (center to center of track).

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10.0 Excavations Close to Metropolitan Facilities

10.1 Shoring Design Submittal
Excavation that impacts Metropolitan’s facilities requires that the contractor submit an engineered shoring design to Metropolitan for review and acceptance a minimum of 30 days before the scheduled start of excavation. Excavation may not begin until the shoring design is accepted in writing by Metropolitan.

Shoring design submittals must include all required trenches, pits, and tunnel or jacking operations and related calculations. Before starting the shoring design, the design engineer should consult with Metropolitan regarding Metropolitan’s requirements, particularly as to any special procedures that may be required.

10.2 Shoring Design Requirements
Shoring design submittals must be stamped and signed by a California registered civil or structural engineer. The following requirements apply:

A. The submitted shoring must provide appropriate support for soil adjacent to and under Metropolitan’s facilities.

B. Shoring submittals must include detailed procedures for the installation and removal of the shoring.

C. Design calculations must follow the Title 8, Chapter 4, Article 6 of the California Code of Regulations (CCR) guidelines. Accepted methods of analysis must be used.

D. Loads must be in accordance with the CCR guidelines or a soils report by a geotechnical consultant.

E. All members must be secured to prevent sliding, falling, or kickouts.

Metropolitan’s pipelines must be located by potholing under Metropolitan’s supervision before the beginning construction. Use of driven piles within 20 feet of the centerline of Metropolitan’s pipeline is not allowed. Piles installed in drilled holes must have a minimum 2-foot clearance between Metropolitan’s pipeline and the edge of the drilled hole, and a minimum of 1-foot clearance between any part of the shoring and Metropolitan’s pipeline.

11.0 Support of Metropolitan Facilities

11.1 Support Design Submittal
If temporary support of a Metropolitan facility is required, the contractor shall submit a support design plan to Metropolitan for review and approval a minimum of 30 days before the scheduled start of work. Work may not begin until the support design is approved in writing by Metropolitan. Before starting design, the design engineer should consult with Metropolitan regarding Metropolitan’s requirements.

11.2 Support Design Requirements
Support design submittals must be prepared, stamped, and signed by a California registered civil or structural engineer. The following requirements apply:

B. Design calculations must follow accepted practices, and accepted methods of analysis must be used.

C. Support designs must show uniform support of Metropolitan’s facilities with minimal deflection.

D. The total weight of the facility must be transferred to the support system before supporting soil is fully excavated.

E. All members must be secured to prevent sliding, falling, or kickouts.

12.0 Backfill

12.1 Metropolitan Pipeline Not Supported
In areas where a portion of Metropolitan pipeline is not supported during construction, the backfill under and to an elevation of 6 inches above the top of the pipeline must be one-sack minimum cement sand slurry. To prevent adhesion of the slurry to Metropolitan’s pipeline, a minimum 6-mil-thick layer of polyethylene sheeting or similar approved sheeting must be placed between the concrete support and the pipeline.

12.2 Metropolitan Pipeline Partially Exposed
In areas where a Metropolitan pipeline is partially exposed during construction, the backfill must be a minimum of 6 inches above the top of the pipeline with sand compacted to minimum 90 percent compaction.

12.3 Metropolitan Cut and Cover Conduit on Colorado River Aqueduct (CRA) In areas where a Metropolitan cut and cover conduit is exposed, the following guidelines apply:

A. No vehicle or equipment shall operate over or cross the conduit when the cover is less than 3 feet.

B. Track-type dozer with a gross vehicle weight of 12,000 lbs or less may be used over the conduit when the cover is a minimum of 3 feet.

C. Wheeled vehicles with a gross vehicle weight of 8,000 lbs or less may operate over the conduit when the cover is a minimum of 4 feet.

D. Tracked dozer or wheeled vehicle should be used to push material over the conduit from the side.

E. Tracked dozer or wheeled vehicle should gradually increase cover on one side of the conduit and then cross the conduit and increase cover on the other side of the conduit. The cover should be increased on one side of the conduit until a maximum of 2 feet of fill has been placed. The cover over the conduit is not allowed to be more than 2 feet higher on one side of the conduit than on the other side.

F. The cover should be gradually increased over the conduit until the grade elevations have been restored.

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13.0 Piles

13.1 Impacts on Metropolitan Pipelines
Pile support for structures could impose lateral, vertical and seismic loads on Metropolitan’s pipelines. Since the installation of piles could also cause settlement of Metropolitan pipelines, a settlement and/or lateral deformation study may be required for pile installations within 50 feet of Metropolitan’s pipelines. Metropolitan may require additional information per its Geo-technical Guidelines for pile installation. Please contact Metropolitan’s Substructures Team for a copy of the Geotechnical Guidelines.

13.2 Permanent Cast-in-place Piles
Permanent cast-in-place piles must be constructed so that down drag forces of the pile do not act on Metropolitan’s pipeline. The pile must be designed so that down drag forces are not developed from the ground surface to springline of Metropolitan’s pipeline.

Permanent cast-in-place piles shall not be placed closer than 5 feet from the edge of Metropolitan’s pipeline. Metropolitan may require additional information per its Geotechnical Guidelines for pile installation. Please contact Metropolitan’s Substructures Team for a copy of the Geotechnical Guidelines.

14.0 Protective Slabs for Road Crossings Over Metropolitan Pipelines Protective slabs must be permanent cast-in-place concrete protective slabs configured in accordance with Drawing SK-1 (See Figure 2 on Page 22).

The moments and shear for the protective slab may be derived from the American Association of State Highway and Transportation Officials (AASHTO). The following requirements apply:

A. The concrete must be designed to meet the requirements of AASHTO B. Load and impact factors must be in accordance with AASHTO. Accepted methods of analysis must be used.

C. The protective slab design must be stamped and signed by a California registered civil or structural engineer and submitted to Metropolitan with supporting calculations for review and approval.

Existing protective slabs that need to be lengthened can be lengthened without modification, provided the cover and other loading have not been increased.

15.0 Blasting
At least 90 days prior to the start of any drilling for rock excavation blasting, or any blasting in the vicinity of Metropolitan’s facilities, a site-specific blasting plan must be submitted to Metropolitan for review and approval. The plan must consist of, but not be limited to, hole diameters, timing sequences, explosive weights, peak particle velocities (PPV) at Metropolitan pipelines/structures, and their distances to blast locations. The PPV must be estimated based on a site-specific power law equation. The power law equation provides the peak particle velocity versus the scaled distance and must be calibrated based on measured values at the site.

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16.0 Metropolitan Plan Review Costs, Construction Costs and Billing

16.1 Plan Review Costs
Metropolitan plan reviews requiring 8 labor hours or less are generally performed at no cost to the project proponent. Metropolitan plan reviews requiring more than 8 labor hours must be paid by the project proponent, unless the project proponent has superior rights at the project area. The plan review will include a written response detailing Metropolitan’s comments, requirements, and/or approval.

A deposit of funds in the amount of the estimated cost and a signed letter agreement will be required from the project proponent before Metropolitan begins or continues a detailed engineering plan review that exceeds 8 labor hours.

16.2 Cost of Modification of Facilities Performed by Metropolitan Cost of modification work conducted by Metropolitan will be borne by the project proponent, when Metropolitan has paramount/prior rights at the subject location.

Metropolitan will transmit a cost estimate for the modification work to be performed (when it has paramount/prior rights) and will require that a deposit, in the amount of the estimate, be received before the work will be performed.

16.3 Final Billing
Final billing will be based on the actual costs incurred, including engineering plan review, inspection, materials, construction, and administrative overhead charges calculated in accordance with Metropolitan’s standard accounting practices. If the total cost is less than the deposit, a refund will be made; however, if the cost exceeds the deposit, an invoice for the additional amount will be forwarded for payment.

17.0 Street Vacations and Reservation of Easements for Metropolitan A reservation of an easement is required when all or a portion of a public street where Metropolitan facilities are located is to be vacated. The easement must be equal to the street width being vacated or a minimum 40 feet. The reservation must identify Metropolitan as a “public entity” and not a “public utility,” prior to recordation of the vacation or tract map. The reservation of an easement must be submitted to Metropolitan for review prior to final approval.

18.0 Metropolitan Land Use Guidelines
If you are interested in obtaining permission to use Metropolitan land (temporary or long term), a Land Use Form must be completed and submitted to Metropolitan for review and consideration.

A nonrefundable processing fee is required to cover Metropolitan’s costs for reviewing your request. Land Use Request Forms can be found at:
http://mwdh2o.com/PDF Doing Your Business/4.7.1 Land Use Request form revised.pdf The request should be emailed to [email protected],or contact the Real Property Development and Management (RPDM) Group at (213) 217-7750.

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After the initial application form has been submitted, Metropolitan may require the following in order to process your request:

A. A map indicating the location(s) where access is needed, and the location & size (height, width and depth) of any invasive subsurface activity (boreholes, trenches, etc.).

B. The California Environmental Quality Act (CEQA) document(s) or studies that have been prepared for the project (e.g., initial study, notice of exemption, Environmental Impact Report (EIR), Mitigated Negative Declaration (MND), etc.).

C. A copy of an ACORD insurance certification naming Metropolitan as an additional insured, or a current copy of a statement of self-insurance.

D. Confirmation of the legal name of the person(s) or entity(ies) that are to be named as the permittee(s) in the entry permit.

E. Confirmation of the purpose of the land use.

F. The name of the person(s) with the authority to sign the documents and any specific signature title block requirements for that person or any other persons required to sign the document (i.e., legal counsel, Board Secretary/Clerk, etc.).

G. A description of any vehicles that will have access to the property. The exact make or model information is not necessary; however, the general vehicle type, expected maximum dimensions (height, length, width), and a specific maximum weight must be provided.

Land use applications and proposed use of the property must be compatible with Metropolitan’s present and/or future use of the property. Any preliminary review of your request by Metropolitan shall not be construed as a promise to grant any property rights for the use of Metropolitan’s property.

19.0 Compliance with Environmental Laws and Regulations As a public agency, Metropolitan is required to comply with all applicable environmental laws and regulations related to the activities it carries out or approves. Consequently, project plans, maps, and other information must be reviewed to determine Metropolitan’s obligations pursuant to state and federal environmental laws and regulations, including, but not limited to:

A. California Environmental Quality Act (CEQA) (Public Resources Code 21000-21177) and the State CEQA Guidelines (California Code of Regulations, Title 14, Division 6, Chapter 3, Sections 1500-15387)
B. Federal Endangered Species Act (ESA) of 1973, 16 U.S.C. §§ 1531, et seq.

C. California Fish and Game Code Sections 2050-2069 (California ESA) D. California Fish and Game Code Section 1602
E. California Fish and Game Code Sections 3511, 4700, 5050 and 5515 (California fully protected species)
F. Federal Migratory Bird Treaty Act (MBTA), 16 U.S.C. §§ 703-712 G. Federal Clean Water Act (including but not limited to Sections 404 and 401) 33 U.S.C. §§ 1342, 1344)
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H. Porter Cologne Water Quality Control Act of 1969, California Water Code §§ 13000- 14076.

I. Title 22, California Code of Regulations, Chapter 16 (California Waterworks Standards), Section 64572 (Water Main Separation)
Metropolitan may require the project applicant to pay for any environmental review, compliance and/or mitigation costs incurred to satisfy such legal obligations.

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20.0 Paramount Rights / Metropolitan’s Rights within Existing Rightsof-Way Facilities constructed within Metropolitan’s rights-of-way shall be subject to the paramount right of Metropolitan to use its rights-of-way for the purpose for which they were acquired. If at any time Metropolitan or its assigns should, in the exercise of their rights, find it necessary to remove or relocate any facilities from its rights-of-way, such removal and replacement or relocation shall be at the expense of the owner of the facility.

21.0 Disclaimer and Information Accuracy
Metropolitan assumes no responsibility for the accuracy of the substructure information herein provided. The user assumes responsibility for verifying substructure locations before excavating and assumes all liability for damage to Metropolitan’s facilities as a result of such excavation.

Additionally, the user is cautioned to conduct surveys and other field investigations as you may deem prudent, to assure that your project plans are correct. The relevant representative from Metropolitan must be called at least two working days, before any work activity in proximity to Metropolitan’s facilities.

It generally takes 30 days to review project plans and provide written responses. Metropolitan reserves the right to modify requirements based on case-specific issues and regulatory developments.

Docusign Envelope ID: FC83EA4B-94DE-46CF-AA93-BAEF385EEAF2 The Metropolitan Water District of Southern California IMPROVEMENTS AND CONSTRUCTION GUIDELINES Issue Date: July 2018 Page 18 of 22
Table 1: General Guidelines for Pipeline Separation between Metropolitan’s Pipeline1 and Sanitary Sewer2 or Hazardous Fluid Pipeline3
Pipeline Crossings Metropolitan requires that sanitary sewer and hazardous fluid pipelines that cross Metropolitan’s pipelines have special pipe construction (no joints) and secondary containment4
. This is required
for the full width of Metropolitan’s rights-of-way or within 10 feet tangent to the outer edges of Metropolitan’s pipeline within public streets. Additionally, sanitary sewer and hazardous fluid pipelines crossing Metropolitan’s pipelines must be perpendicular and maintain a minimum 1-foot vertical clearance between the top and the bottom of Metropolitan’s pipeline and the pipe casing.

These requirements apply to all sanitary sewer crossings regardless if the sanitary sewer main is located below or above Metropolitan’s pipeline.

Parallel Pipeline Metropolitan generally does not permit the installation of longitudinal pipelines along its rights-of-way. Within public streets, Metropolitan requires that all parallel sanitary sewer, hazardous fluid pipelines and/or non-potable utilities be located a minimum of 10 feet from the outside edges of Metropolitan’s pipelines. When 10-foot horizontal separation criteria cannot be met, longitudinal pipelines require special pipe construction (no joints) and secondary containment4 .

Sewer Manhole Sanitary sewer manholes are not allowed within Metropolitan’s rights-of-way. Within public streets, Metropolitan requests manholes parallel to its pipeline be located a minimum of 10 feet from the outside edges of its pipelines. When 10 foot horizontal separation criteria cannot be met, the structure must have secondary containment5
.

Notes:
1 Separation distances are measured from the outer edges of each pipe. 2 Sanitary sewer requirements apply to all recycled water treated to less than disinfected tertiary recycled water (disinfected secondary recycled water or less). Recycled water definitions are included in Title 22, California Code of Regulations, Chapter 3 (Water Recycling Criteria), Section 60301. 3 Hazardous fluids include e.g., oil, fuels, chemicals, industrial wastes, wastewater sludge, etc. 4 Secondary Containment for Pipeline - Secondary containment consists of a continuous pipeline sleeve (no joints).

Examples acceptable to Metropolitan include welded steel pipe with grout in annular space and cathodic protection (unless coated with non-conductive material) and High Density Polyethylene (HDPE) pipe with fusion-welded joints. 5 Secondary Containment for Structures – Secondary containment consists of external HDPE liner or other approved method.

Additionally, pipelines crossing Metropolitan’s pipelines must be perpendicular and maintain a minimum 1-foot vertical clearance.

Parallel Pipeline Metropolitan generally does not permit the installation of longitudinal pipelines along its rights-of-way. Within public streets, Metropolitan requests that all parallel pipelines be located a minimum of 10 feet from the outside edges of
Metropolitan’s pipelines. When 10-foot horizontal separation criteria cannot be met, special pipe construction (no joints) or secondary containment3 are required.

Storm Drain
Manhole
Permanent utility structures (e.g., manhole. catch basin, inlets) are not allowed within Metropolitan’s rights-of-way. Within public streets, Metropolitan requests all structures parallel to its pipeline be located a minimum of 10 feet from the outside edges of its pipelines. When 10 foot horizontal separation criteria cannot be met, the structure must have secondary containment4
.

Notes:
1 Separation distances are measured from the outer edges of each pipe. 2 Disinfected tertiary recycled water as defined in Title 22, California Code of Regulations, Chapter 3 (Water Recycling Criteria), Section 60301.
3 Secondary Containment for Pipeline - Secondary containment consists of a continuous pipeline sleeve (no joints).

Examples acceptable to Metropolitan include welded steel pipe with grout in annular space and cathodic protection (unless coated with non-conductive material) and High Density Polyethylene (HDPE) pipe with fusion-welded joints. 4 Secondary Containment for Structures – Secondary containment consists of external HDPE liner or other approved method.

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Table 3: General Guidelines for Pipeline Separation1 between Metropolitan’s Pipeline and Recycled Water2,4 Irrigations
Pressurized recycled
irrigation mainlines • Crossings - must be perpendicular and maintain a minimum 1-foot vertical clearance. Crossing pressurized recycled irrigation mainlines must be special pipe construction (no joints) or have secondary containment3 within 10-feet tangent to the outer edges of Metropolitan’s pipeline.
• Longitudinal - must maintain a minimum 10-foot horizontal separation and route along the perimeter of Metropolitan’s rightsof-way where possible.

Intermittently
Energized Recycled
Water Irrigation
System Components
• Crossings - must be perpendicular and maintain a minimum 1-foot vertical clearance. Crossing irrigation laterals within 5-feet tangent to the outer edges of Metropolitan’s pipeline must be special pipe construction (no joints) or have secondary containment3 .
• Longitudinal – must maintain a minimum 5-foot horizontal separation between all intermittently energized recycled water irrigation system components (e.g. irrigation lateral lines, control valves, rotors) and the outer edges of Metropolitan’s pipeline.

Longitudinal irrigation laterals within 5-feet tangent to the outer edges of Metropolitan’s pipeline must be special pipe construction (no joints) or have secondary containment3
.

Irrigation Structures Irrigation structures such as meters, pumps, control valves, etc. must be located outside of Metropolitan’s rights-of-way.

Irrigation spray rotors
near Metropolitan’s
aboveground facilities
Irrigation spray rotors must be located a minimum of 20-foot from any Metropolitan above ground structures with the spray direction away from these structures. These rotors should be routinely maintained and adjusted as necessary to ensure no over-spray into 20-foot clear zones.

Irrigations near open
canals and aqueducts
Irrigation with recycled water near open canals and aqueducts will require a setback distance to be determined based on site-specific conditions. Runoff of recycled water must be contained within an approved use area and not impact Metropolitan facilities.

Appropriate setbacks must also be in place to prevent overspray of recycled water impacting Metropolitan’s facilities.

Notes:
1 Separation distances are measured from the outer edges of each pipe. 2 Requirements for recycled water irrigation apply to all levels of treatment of recycled water for non-potable uses.

Recycled water definitions are included in Title 22, California Code of Regulations, Chapter 3 (Water Recycling Criteria), Section 60301.
3 Secondary Containment for Pipeline - Secondary containment consists of a continuous pipeline sleeve (no joints).

Examples acceptable to Metropolitan include welded steel pipe with grout in annular space and cathodic protection (unless coated with non-conductive material) and High Density Polyethylene (HDPE) pipe with fusion-welded joints. 4 Irrigation with recycled water shall not be applied directly above Metropolitan’s treated water pipelines.

Docusign Envelope ID: FC83EA4B-94DE-46CF-AA93-BAEF385EEAF2 The Metropolitan Water District of Southern California IMPROVEMENTS AND CONSTRUCTION GUIDELINES Issue Date: July 2018 Page 21 of 22
Figure 1: AASHTO H-20 Loading
Note: The H loadings consist of a two-axle truck or the corresponding lane loadings as illustrated above. The H loadings are designated “H” followed by a number indicating the gross weight in tons of the standard truck.

Docusign Envelope ID: FC83EA4B-94DE-46CF-AA93-BAEF385EEAF2

Certificate Of Completion
Envelope Id: FC83EA4B-94DE-46CF-AA93-BAEF385EEAF2 Status: Completed Subject: Complete with Docusign: Brea_2050 FGPU-CSP_Comment Letter_DPEIR_3-2-2026_final draft.docx, Brea...

Source Envelope:

Document Pages: 31 Signatures: 1 Envelope Originator:

Certificate Pages: 1 Initials: 0 Christine H Saito
AutoNav: Enabled
EnvelopeId Stamping: Enabled
Time Zone: (UTC-08:00) Pacific Time (US & Canada)
700 N Alameda St
Los Angeles, CA 90012
[email protected]
IP Address: 144.166.55.172
Record Tracking
Status: Original
3/16/2026 5:39:53 PM
Holder: Christine H Saito
[email protected]
Location: DocuSign
Signer Events Signature Timestamp
Sean Carlson
[email protected]
Team Mgr-Environ Planning
Metropolitan Water District
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Using IP Address: 144.166.53.174
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Signed: 3/17/2026 8:28:26 AM
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Jolene Ditmar
[email protected]
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Sent: 3/16/2026 5:44:40 PM
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Brea 2050 Public Hearing Draft General Plan Goals Policies and Actions (April 2026, Version 2)

Page 1 of 45 ends

Brea City CouncilJune 2, 2026

Brea City Council
June 2, 2026