5.1 INTRODUCTION

In accordance with CEQA (CEQA Guidelines Section 15130 et seq.), this section presents an analysis of cumulative impacts that may result from construction and operation of the proposed Project. As defined in Section 15355 of the CEQA Guidelines, cumulative impacts refers to two or more individual effects which, when considered together, are considerable or which compound or increase other environmental impacts. In compliance with CEQA, this section of the PEA examines incremental impacts of the proposed Project in combination with effects of other past, present, and reasonably foreseeable future projects. The analysis considers the potential for both short-term and long-term cumulative impacts. Short-term impacts are those related primarily to project construction, and long-term impacts are those related primarily to permanent project features or operation of the project.

5.2 TECHNICAL METHODOLOGY AND SIGNIFICANCE CRITERIA

The cumulative analysis is based on a list of past, present, and reasonably foreseeable future projects that may be constructed or commence operation during the timeframe of activity associated with the proposed Project. These include larger scale projects located within 5 miles of the proposed Project.

The cumulative projects were identified based on data obtained from SCE, local jurisdictions, Southern California Association of Governments (SCAG), Intergovernmental Review Clearinghouse Reports, South Coast Air Quality Management District (SCAQMD) CEQA document review logs, and environmental documents. The analyses of cumulative effects for each issue area utilize this information to estimate the potential for combined effects of the proposed Project and other projects in the vicinity. However, the geographic scope of analysis and the range of projects vary for each environmental issue area.

According to the Office of Planning and Research (OPR), which provides CEQA Guidelines in Section 15355, cumulative impacts refers to two or more individual effects which, when considered together, are considerable or which compound or increase other environmental impacts. The cumulative impact from several projects is the change in the environment which results from the incremental impact of the project when added to other closely related past, present and reasonably foreseeable probable future projects. Cumulative impacts can result from individually minor but collectively significant projects taking place over a period of time. When the combined cumulative impact associated with the project’s incremental effect and the effects of other projects is not significant, the discussion shall briefly indicate why the cumulative impact is not significant and is not discussed in further detail.

CEQA Guidelines provide the following guidance regarding cumulative impact significance:

“Projects can cause significant impacts by direct changes to the environment or by triggering reasonably foreseeable indirect physical changes. Physical changes caused by a project can contribute incrementally to cumulative effects that are significant, even if individual changes resulting from a project are limited. You must determine whether the cumulative impact is significant, as well as whether an individual effect is “cumulatively considerable”…

When considering the relationship between the cumulative condition and the incremental effect of an individual project, keep in mind “The mere existence of significant cumulative impacts caused by other projects alone shall not constitute substantial evidence that the proposed Project’s incremental effects are cumulatively considerable” (Guidelines Section 15064(h)(4)” (Note: emphasis added).

5.3 CUMULATIVE PROJECTS

Over 180 past, present, and reasonably foreseeable future projects have been identified within a 5-mile radius of the proposed Project (Figure 5.3-1 [Sheet 1, 2] ). These projects include large-scale wind farms, large-scale planned residential communities, small-scale residential projects, infill and redevelopment, commercial, industrial, public services, transportation, one oil and gas pipeline conversion, recreational projects, and two resource management projects on the Angeles National Forest (ANF). These projects are summarized in Table 5.3-1 and listed individually in Table 5.3-2 (note: due to its length, Table 5.3-2 is presented at the end of this section). The project summary indicates that cumulative project areas total more than 167,000 acres of land, the majority of which are associated with large-scale planned communities (57 percent) and wind-energy related projects (27 percent).

Large-scale planned developments would collectively result in the construction of more than 60,000 homes and associated commercial developments, schools, recreational facilities, road networks, and public utilities on more than 95,000 acres. The largest residential projects concentrate in the Antelope Valley north of the ANF but substantial residential developments also occur south of the ANF in the vicinity of Duarte and Azusa, unincorporated land near Brea and Yorba Linda, and in Chino and Ontario (see Figure 5.3-1 [Sheet 1, 2] ). These follow a similar pattern of development in that they primarily target undeveloped land adjacent to established urban areas. Small-scale residential projects are also proposed throughout the proposed Project area north and south of the ANF. Collectively, these residential projects reflect California’s growing need for affordable housing and the availability of relatively inexpensive land in the Antelope Valley and the Inland Empire.

Energy-related projects account for another 47,000 acres of the total acreage associated with cumulative projects. Virtually all of this acreage reflects the construction of large wind energy “farms” that would be developed in the Tehachapi area in Kern County (see Figure 5.3-1 [Sheet 1, 2] ). Because the TRTP is designed in part to provide interconnection for proposed wind energy projects, they are described in more detail below.

TABLE 5.3-1
SUMMARY OF CUMULATIVE PROJECTS¹

¹   Sources: See Section 5.2.

5.3.1 Energy and Transmission Projects

5.3.1.1 Proposed Wind Generation Facilities

SCE is obligated to interconnect power generation facilities, including wind farms, into its electrical system, per Section 210 and 212 of the Federal Power Act (16 U.S.C. § 824 [i] and [k]) and Sections 24 and 25 of the California Independent System Operator’s (CAISO) Tariff. There are wind generation facilities currently in the ISO Interconnection Queue for the Tehachapi area (CAISO, 2007). Most of these Tehachapi-area wind facilities are currently in the planning stage and information about these potential projects is limited at this time. Despite this limitation, the general environmental effects of wind energy projects are known because there are many operating wind energy facilities in California. In addition, the characteristics of the latest generation of wind turbine technology are known, including descriptions of their physical components and operation. Further, environmental impact analysis has been conducted for recent wind energy proposals, including the Pine Tree Wind Project being planned by the Los Angeles Department of Water and Power (LADWP) north of Mojave, California. This information can be used to estimate the environmental effects of future wind energy facilities in the Tehachapi region for the purposes of cumulative impact analysis.

As listed above, the May 2007 CAISO Interconnection Queue lists wind generation facilities anticipated to be constructed in the Tehachapi area. The following is a discussion of proposed Projects in the Interconnection Queue for which preliminary planning information is available. These projects are listed in Table 5.3-2 and identified on Figure 5.3-1 [Sheet 1, 2] .

LADWP proposes to build the Pine Tree Wind Project, an 8,000-acre wind farm development located about 12 miles north of Mohave. While outside the 5-mile radius of the proposed Project, the Pine Tree Wind Project is discussed here because of its similarity to other wind projects considered in this discussion. The project would have 120 megawatts (MW) of total generation capacity and would include construction of 80 wind turbines, several meteorological towers, a substation, an 8-mile-long transmission line, switching station, operations and maintenance (O&M) building, and access roads. The Pine Tree Wind Project EIR/EA was approved by the United States Department of the Interior (USDI) Bureau of Land Management (BLM) and LADWP in 2006 and the Project will be interconnected to the LADWP transmission system.

The PdV Wind Energy Project is proposed by Southwest Power Partners, LLC and would be located on a 6,275-acre site in the south Tehachapi Mountains. The PdV project would be capable of generating approximately 300 MW, and would include onsite and offsite access roads, control cables, subsurface feeder line corridors located outside the project area, a 20-acre interconnection yard/switching station known as the Cottonwind Substation, an O&M building, and temporary construction laydown area. The project filed a Notice of Preparation (NOP) with Kern County in June 2006 for the preparation of an Environmental Impact Report (EIR).

The Alta Wind Energy Center is being developed by Alta Innovative Power Co, LLC, which is a joint venture between Allco Wind Energy and Oak Creek Energy Systems. The project encompasses a 50 square mile area (32,000 acres) located between Mohave and Tehachapi. The project is anticipated to generate up to 1,500 MW. Allco Wind Energy signed a 20-year Power Purchase Agreement (PPA) with SCE in December 2006 for the electric output from this wind farm. Construction is expected to occur between 2009 and 2014, with operation planned in October 2007. The Windridge Operating Wind Farm, which is proposed by Aero Energy, LLC (Western Wind Energy Corporation), involves the development of a 192-acre wind farm near Tehachapi-Willow Springs Road with a 4.5 MW generation capacity and future expansion to 12 MW. Windridge Operating Wind Farm has a PPA with SCE to supply output no later than 2014.

The WindStar Project, which is another Aero Energy, LLC (Western Wind Energy Corporation) development, is planned to generate 120 MW on a 1,062-acre site within the Tehachapi Pass Wind Park. The Windstar Project signed a PPA with SCE to supply output no later than December 31, 2008.

5.3.1.2 Antelope Transmission Project

Wind farm development is concentrated approximately 25 miles north of SCE’s Antelope Substation, in the Tehachapi Wind Resource Area. The Antelope Transmission Project is an approved project that will provide a portion of the infrastructure necessary to interconnect wind power generation in the Tehachapi area for delivery to southern California customers.

The Antelope Project consists of three segments. Segment 1 of the Antelope Transmission Project involves construction of a new 26-mile 500-kV transmission line between SCE’s existing Antelope and Pardee substations located in the City of Lancaster and the City of Santa Clarita, respectfully. Segment 1 is estimated to begin construction in November 2007 and commence operations in December 2008. Segments 2 and 3 of the Antelope Transmission Project will include approximately 56 miles of new 500/220 kV transmission lines and related facilities that will bring electricity from the Tehachapi Wind Resource Area in southern Kern County to the existing Antelope Substation in the City of Lancaster, then farther south to the existing Vincent Substation near Acton in unincorporated Los Angeles County. Construction of Segments 2 and 3 is scheduled to begin in March 2008 and end in April 2009.

5.4 POPULATION GROWTH FORECAST

In addition to the list of cumulative projects presented in Table 5.3-2, general growth trends forecasted by SCAG and the Kern County Council of Governments (COG) were utilized to characterize anticipated population and employment growth in Kern County, Los Angeles County, and San Bernardino County, as presented in Table 5.4-1. This information provides a general understanding of the types of physical changes expected in the area and the potential for impacts that could combine with the impacts of the proposed TRTP. As a regional planning agency, SCAG forecasts growth projections up to 25 years into the future and Kern County COG forecasts growth projections up to 50 years by incorporating recently available information from international, federal, and State statistical agencies, along with subregions and local jurisdictions (SCAG, 2004a; COG, 2006).

TABLE 5.4-1
REGIONAL GROWTH PROJECTIONS¹

¹   Sources: SCAG, 2004a; SCAG, 2004b; COG 2006.

²   N/A: Data is unavailable.

As shown in Table 5.4-1, the three counties in the TRTP study area are expected to experience substantial population growth between 2000 and 2030, with a 68.5 percent population increase in Kern County, a 27.6 percent increase in Los Angeles County, and a 58.7 percent increase in San Bernardino County. Population growth of this magnitude directly affects the demand for jobs and housing and contributes to cumulative impacts as public and private sector decision makers respond by increasing the number of residential commercial, industrial, public service, and transportation projects to accommodate larger populations.

5.5 CUMULATIVE IMPACT ANALYSIS BY ISSUE AREA

5.5.1 Aesthetics

The geographic extent for the analysis of cumulative impacts to Visual Quality is defined as a 10-mile-wide corridor that follows the center line (5 miles on either side) of the proposed Project route. Although views can and do extend beyond 5 miles, the 5-mile distance was chosen because it would include the foreground and middleground distance zones and would be a useful distance to gauge cumulative impacts within the Antelope Valley, the San Gabriel Mountains/ANF, and the San Gabriel Valley and Inland Empire landscape regions.

The locations of past, present, and reasonably foreseeable future projects within 5 miles of the proposed Project are indicated on Figure 5.3-1 [Sheet 1, 2] and these projects are identified and briefly described in Tables 5.3-1 and 5.3-2. These data indicate that more than 165,000 acres of land within the cumulative impact corridor are likely to be developed over the next several decades. Much of the proposed development consists of large-scale residential and commercial projects that would collectively result in the construction of more than 60,000 homes. Many of the areas along the proposed Project route have experienced significant growth and visual change in recent years, and the apparent continuation of development along and near the route will continue to change the visual characteristics of the landscape in a number of specific areas.

5.5.1.1 Cumulative Impact Analysis

The paragraphs that follow evaluate whether the proposed Project has the potential to cause cumulative impacts to the visual resources of the project area. More specifically, the analysis considers whether the cumulative projects and the TRTP would have a cumulatively significant impact on the area’s aesthetics and whether the TRTP’s contribution to those impacts would be cumulatively considerable.

Would the Project have a substantial adverse effect on a scenic vista?

The only scenic vistas identified in the proposed Project area are the views from the viewing points designated along the trail system in the Antelope Valley California Poppy Reserve from which Segment 4 would be visible 1.4 miles in the distance. Because analysis of the proposed Project’s aesthetic impacts on these views has established that the impacts would be negligible, the TRTP’s incremental contribution to any cumulative impact that might occur in the area seen from these viewpoints would not be cumulatively considerable. Therefore, no mitigation measures to address cumulative impacts related to effects on the views from these scenic vistas are required.

Would the Project substantially damage scenic resources, including, but not limited to, trees, rock outcroppings, and historic buildings within a state scenic highway?

The only adopted state scenic highways that would be crossed by the proposed Project are the Angeles Crest Highway in the ANF that would be crossed by Segments 6 and 11, and the portion of Highway 57 between Brea and Diamond Bar in the South of the ANF region that would be crossed by Segment 8. Because no projects are proposed in the vicinity of Segment 6 and 11 crossings of the Angeles Crest Highway, or the Segment 8 crossing of Highway 57, there would be no cumulative impacts and, therefore, mitigation measures to address cumulative impacts related to state scenic highways are not required.

Would the Project substantially degrade the existing visual character or quality of the site and its surroundings?

As review of Figure 5.3-1 [Sheet 1, 2] suggests, the cumulative impacts can be described in terms of three fairly distinct geographic areas that exhibit different geographic and jurisdictional characteristics that affect the nature, type, and intensity of development. These three areas include the lands north of the ANF, the lands on the ANF, and the lands south of the ANF. The impacts on visual character and quality are evaluated in terms of the proposed Project’s effects in these three regions.

5.5.1.1.1 North of the ANF. Recent growth throughout the Antelope Valley and in the portion of the Tehachapi Mountains immediately north of the proposed Project route has resulted in changes to the natural landscape character. Major visual changes have occurred in the Tehachapi Mountains (particularly in the Tehachapi Wind Resource Area) as a result of the development of wind farms, substations, transmission lines, roads, and maintenance facilities. Parts of natural-appearing mountain landscapes have been changed into landscapes in which large infrastructure facilities are a part of the landscape pattern. The development of industrial manufacturing facilities at Cal Cement and Monolith in the valley floor just south of the Tehachapi Mountains have changed the character of the area from natural to partially industrial. The presence of existing transmission corridors that pass through Kern and Los Angeles counties have also played a part in altering the natural landscape character of parts of the Antelope Valley. Farther south along the proposed Project route, near the cities of Palmdale and Lancaster, the natural character of the landscape has been converted from natural or agricultural in many locations to suburban residential as a result of the development of numerous large-scale residential subdivisions.

Proposed future projects will continue to change the character of the landscape along the proposed Project route. Proposed projects include at least five wind energy projects in the Tehachapi area, the largest of which include the 32,000-acre Alta Wind Energy Center Project, the 8,000-acre Pine Tree Wind Project, and the 6,400-acre PdV Wind Energy Project. All of these projects would require additional substation and transmission capacity, some of which will be provided by the approved but not yet developed Antelope Transmission Projects (Segment 1, and Segments 2 and 3). As a part of the Antelope Transmission Project Segment 1 (Antelope-Pardee) 500 kV transmission project, a major expansion of the Antelope Substation has been approved. Figure 5.5-1 presents a simulation that depicts a view of this substation as it would appear with the expansion approved as a part of the Antelope Transmission Project Segment 1 as well as the further expansion proposed as a part of TRTP.

In the central and southern portions of the Antelope Valley, other potential future large-scale projects include more large residential subdivisions (that would construct up to 29,000 residential units), commercial developments, and associated infrastructure. These developments would occur on approximately 24,000 acres (Table 5.3-2). The proposed Projects would replace open, largely natural and agricultural appearing landscapes with subdivisions and other features that would have more developed character. The largest example of this type of new development is the Ritter Ranch Master Planned Community located in the hills above Palmdale. This extensive development would impact approximately 11,520 acres of undeveloped land and eventually will include over 7,000 homes, 7 schools, 1 golf course, and approximately 75 acres of commercial development. The landscape character of this large area would change over time from natural to suburban residential.

The cumulative developments described in the Antelope Valley landscape unit are expected to substantially alter the visual character and quality of the landscape in this area, creating an impact that would be considered to be cumulatively significant. While the TRTP will create some changes to visual character and quality, these would be small to moderate, localized in nature, and less than significant. Because the visual changes brought about by TRTP would be incrementally negligible, the TRTP’s incremental contribution to the cumulative impact on the character and quality of the landscape in the Antelope Valley area would not be cumulatively considerable. As a consequence, no mitigation measures to address cumulative impacts on visual character and quality in this area are required.

5.5.1.1.2 The ANF. Segments 6 and 11 traverse the San Gabriel Mountain range, which lies within the boundaries of the ANF. In this area, the proposed routes travel across rugged, mountainous terrain with deeply incised drainages and canyons. There are relatively few developed areas along the routes through which the two segments would pass and there are relatively few planned actions that would change the character of the landscape across which the segments would be constructed. Several resource management projects are planned that would have minor affects on visual character or on consistency with the Forest Plan’s visual resource objectives. They include a fuels management project to reduce the risk of fire in Devil’s Canyon and a restoration and reconstruction project to restore and recover hydrological, biological, cultural, recreational and other values in Rubio Canyon. The ANF may issue Special Use Permits for up to 495 recreational residential units currently or formerly located on 18 tracts of forest land. Many of these residences were destroyed by wildfires in 2002.

Because the changes to visual character and quality likely to be brought about by the recent and future cumulative projects located in the portions of the ANF within 5 miles of Segments 6 and 11 will be relatively minor, there would no cumulative impact to the character and quality of the landscape in this area. As a consequence, no mitigation measures to address cumulative impacts to visual resources in the ANF are required.

5.5.1.1.3 South of the ANF. In the area south of the ANF, the proposed Project segments travel across the San Gabriel Valley, along the ridgeline that defines the valley’s southern end, and extends into the western edge of the Inland Empire. For the most part, the valley floor and hillside areas in this region are covered by urban development that includes neighborhoods of single-family housing on the hillsides, and on the valley floors, a mix of freeways, rail corridors, transmission corridors, gravel extraction areas, industrial areas, commercial uses, other housing of varying densities, and open space areas that serve both flood control and recreation purposes. Because the area south of the ANF is, to a large degree, already built out, there are only two areas where there are concentrations of proposed change that might affect the visual character and quality of the setting. In the Duarte-Irwindale-Azusa area just south of the ANF, a large number of small- to medium-sized residential, commercial, and industrial developments are proposed that would add new visual elements to the setting and intensify the perceived level of urbanization. In the vicinity of Brea, Yorba Linda, Chino Hills, and Chino, eight large residential developments are planned on now open and natural-appearing hillside areas that will result in the construction of more than 30,000 homes. Because, for the most part, the proposed residential projects in this area would be located on narrow, steep-sided hills that are more visible than developments located in the relatively level valleys where much of the previous development in this area has occurred, these developments are likely to have a substantial impact on the character and quality of the visual environment in this portion of the proposed Project area.

The cumulative developments described in the Duarte-Irwindale-Azusa area and in the Brea-Yorba Linda-Chino Hills-Chino area are expected to substantially alter the visual character and quality of the landscape in this area, creating an impact that would be considered to be cumulatively significant. While the TRTP will create some visual changes that in a few places would be significant, the impacts will be limited to areas in close proximity to specific transmission structures. Because of the limited area of the impacts and because these areas are not in immediate proximity to the places where the new developments will be taking place, the changes to visual character and quality brought about by TRTP would be incrementally negligible. Because the proposed Project’s impacts on visual character and quality in the South of the ANF region would be incrementally negligible, the TRTP’s incremental contribution to the cumulative impacts in this area would not be cumulatively considerable. As a consequence, no mitigation measures to address cumulative impacts on visual character and quality in the South of the ANF area are required.

Would the Project create a new source of substantial light or glare that would adversely affect day or nighttime views in the area?

Because the T/L would not be illuminated, it would not be a source of nighttime light and glare. Additionally, the analysis of the proposed Project’s visual resources impacts has established that the T/L would not be a source of daytime glare. Although the development of the Whirlwind Substation and the expansion of the Antelope and Vincent substations will require additional lighting, this lighting will be minimal and shielded and only used when needed, and as a consequence, lighting at these substations will not create significant impacts. Of these three substations, Antelope Substation is the only one located in an area where surrounding proposed development would create light and glare impacts that would have the potential to be cumulatively significant. In this area, the Antelope Substation’s light and glare impacts would be incrementally negligible, that is, the substation’s incremental contribution to the cumulative impact would not be cumulatively considerable. No mitigation measures to address cumulative light and glare impacts are required.

5.5.2 Agricultural Resources

The geographic extent for the analysis of cumulative impacts associated with agricultural resources is a 5-mile zone on either side of the proposed Project (e.g., proposed T/L routes and substation locations). Agricultural resources in this 10-mile-wide zone concentrate north of the Antelope Substation in southern Kern County and northern Los Angeles County and in and adjacent to the cities of Chino and Ontario in southwestern San Bernardino County.

5.5.2.1 Cumulative Impact Analysis

The following analysis evaluates whether the proposed Project has the potential to cause cumulative impacts to agricultural resources. Specific issues addressed in the analysis include the following:

Would the proposed Project in combination with other cumulative projects convert Prime Farmland, Unique Farmland, or Farmland of Statewide Importance (Farmland) to non-agricultural use, conflict with existing zoning for agricultural use, or a Williamson Act contract, or involve other changes in the existing environment which could result in conversion of farmland to non-agricultural use?

The cumulative projects listed in Table 5.3-2 have the potential to collectively affect over 165,000 acres of land. These data, coupled with visual examination of the cumulative project location maps (Figure 5.3-1, Sheets 1 and 2 ) suggest that most development would be located on undeveloped land in southern Kern County and northern Los Angeles County and in the cities of Chino and Ontario in southwestern San Bernardino County. As discussed in Section 4.3 and illustrated on Figure 4.3-1 [Sheet 1, 2, 3, 4, 5, 6, 7, 8, 9] , these areas include a considerable amount of agricultural resources, including all types of Important Farmland, Williamson Act land and large tracts of Grazing Land. The cumulative developments are expected to continue a long-term trend of converting Southern California’s farmlands to residential, commercial and other non-agricultural uses. For example, between 1984 and 2004, the amount of Important Farmlands lost to development was 10.8 percent in Kern County, 50.2 percent in San Bernardino County, and 27.6 percent in Los Angeles County (see land use summary tables in Appendix O). These tables also demonstrate that the rates of conversion are accelerating. Recent trends in the amount of Williamson Act lands are not as severe but also show a substantial and accelerating decline over time.

Cumulative developments thus have converted and are expected to continue to convert substantial amounts of Important Farmland and Williamson Act lands to non-agricultural uses. As per CEQA, this conversion is considered cumulatively significant. While the TRTP would also result in the permanent conversion of such lands, the estimated 21.7 acres of Important Farmland and the 3.4 acres of Williamson Act lands that would be converted as a result of the TRTP are incrementally negligible; that is, the TRTP’s incremental contribution to the cumulative impact would not be cumulatively considerable. No mitigation measures to address cumulative impacts are required.

5.5.3 Air Quality

5.5.3.1 Introduction

The geographic extent for potential air quality related cumulative impacts includes portions of the following counties: Kern, Los Angeles, and San Bernardino counties. These counties are located within the Mojave Desert Air Basin (MDAB) and South Coast Air Basin (SCAB). In the Project area, air quality is regulated by the following three local air districts: Kern County Air Pollution Control District (KCAPCD), the Antelope Valley Air Quality Management District (AVAQMD) and the South Coast Air Quality Management District (SCAQMD) as shown on Figure 4.4-1 in Section 4.4.

The MDAB covers more than 20,000 square miles and is bounded by the San Gabriel and San Bernardino mountains to the south, which serve as the boundary separating the MDAB and the SCAB. The Tehachapi Mountains serve as the northwest boundary separating the MDAB from the San Joaquin Air Basin (SJAB). The majority of the population resides in the southeast area of the MDAB with the remaining population scattered in rural areas. There are approximately 494,000 people residing within the MDAB. Because it is a desert environment consisting of flat terrain, during high wind conditions, a substantial amount of fugitive dust (i.e., particulate matter [PM]) is generated. Air quality in the MDAB is also heavily influenced by airborne pollutants transported into the region from areas within the SCAB under the jurisdiction of the SCAQMD.

The SCAB covers an area of 6,745 square miles and consists of Orange County and the non-desert portions of Los Angeles, Riverside, and San Bernardino counties. It is bounded on the west by the Pacific Ocean, the north by the San Gabriel Mountains, the east by the San Bernardino Mountains, and the south by the Santa Ana Mountains. The SCAB has over 15 million people with one of the worst air quality conditions (e.g., high concentrations of ozone [O₃], carbon monoxide [CO], particulate matter less than or equal to 10 microns [PM₁₀], and PM less than or equal to 2.5 microns [PM_2.5]) in the nation because of the topographical features that trap anthropogenic air pollutants that are associated with the dense population. Mobile source emissions are a major contributor to overall pollution within the SCAB.

For Air Quality, the potential geographic extent of the cumulative impact area covers the aforementioned air basins and counties/jurisdictions. Cumulative impacts could extend over the entire Project route. However, the identification of cumulative projects for air quality typically ranges from within 1 mile of a proposed project to as far as 6 miles or more from a proposed project.The effect of downwind dispersion eliminates the potential for Project-level significant cumulative air quality impacts over areas larger than a few miles. >

Many local air quality jurisdictions provide no guidance regarding the distance for the selection of cumulative projects, as is the case with the AVAQMD and KCAPCD CEQA guidance documents. However, other jurisdictions and agencies use specific radius for specific analysis. The SCAQMD has approved CEQA analyses that have used a 1-mile radius for cumulative project identification, while the California Energy Commission uses a 6-mile radius for operating emissions cumulative impact evaluation for power plants.

Since the proposed Project would have very minor operating emissions, as discussed in Section 4.4, the cumulative impact discussion is focused on construction impacts. Construction impacts are localized and of short duration. The potential for cumulative impacts during construction is limited since the active construction sites are constantly moving along the T/L routes and would not be near other cumulative projects for a long period of time. Additionally, while the proposed Project’s construction emissions are significant on the whole due to the numerous concurrently active construction sites and extensive paved and unpaved traffic, the construction emissions at any one construction site at any one time would not be significant. The impacts from each of the proposed Project’s construction sites would be reduced significantly with distance. Therefore, only projects within 1 mile of the proposed Project routes, as well as projects that could impact traffic during project construction, are considered projects that could cause cumulative impacts. Additionally, only projects that are scheduled concurrently in the same area as the proposed Project (i.e., construction time frames coinciding with April 2009 through November 2013) are considered as projects that could contribute to cumulative impacts, since significant air quality cumulative impacts can only occur from emission sources that are active at the same time.

As discussed in Section 5.3, many reasonably foreseeable future projects have been identified within a 5-mile radius of the TRTP and multiple proposed Projects (e.g., large and small scale residential developments, and wind energy developments) are located within several miles of the proposed TRTP.

Past development and population growth within various cities traversed by the proposed TRTP segments (refer to Section 4.10) and adjacent unincorporated areas have increased the possibility that new projects would contribute to increased air emissions within the MDAB and SCAB.

As shown in Table 4.4-3 in Section 4.0, the Project area in the MDAB is currently designated as a moderate non-attainment area for the 8-hour National Ambient Air Quality Standards (NAAQS) for O₃ and PM₁₀. The Project area in the SCAB is currently designated as a severe non-attainment area for the 8-hour NAAQS for O₃; a serious non-attainment area for CO and PM₁₀; and a non-attainment area for PM_2.5. CARB submitted SCAQMD’s request for a redesignation of the CO attainment status of the SCAB from non-attainment to attainment to the USEPA in 2005. As of February 14, 2007, the USEPA had reviewed the request. It was circulated and comments were solicited until March 16, 2007. After receiving, reviewing, and addressing all the comments, USEPA will decide whether to grant or deny the CO redesignation request. Currently it is unknown when USEPA will make this determination. The Project area in the two air basins is in attainment with the NAAQS for the other applicable criteria pollutants.

5.5.3.2 Cumulative Impact Analysis

The TRTP when considered together with other reasonably foreseeable projects from an air quality perspective has the potential to result in short term air quality impacts that could exacerbate the non-attainment status of the aforementioned applicable pollutants in the Project area.

To determine the potential significance of TRTP-specific air quality impacts associated with the implementation of each proposed TRTP segment, emissions and associated impacts were assessed on a segment-by-segment basis in Sections 4.4.6.1 through 4.4.6.8. To assess the potential significance of air quality impacts within each air basin, daily and annual construction emissions were summed for TRTP segments located in the same air districts and air basin and compared to the applicable air district thresholds. The following discussions address potential cumulative air quality impacts for the proposed TRTP when considered with other reasonably foreseeable cumulative projects that may occur in the same geographic area and have overlapping emissions with the TRTP. It should be noted that the specific timing and/or air emissions associated with the potential cumulative projects listed in Table 5.3-2 are generally not readily available, thus making cumulative impact assessments necessarily general and qualitative.

Would the proposed Project conflict with or obstruct implementation of the applicable air quality plan?

Air quality plans are strategies designed to reduce long-term operational emissions and comply with the federal and State ambient air quality standards. The operation of the TRTP would generate emissions considered to be negligible. Operational emissions are considered to be negligible because the primary source of emissions would be from maintenance vehicles used by workers to visit the substations and patrol the T/L routes. TRTP operation emissions would be negligible and well below the significance thresholds, and would not create significant air quality impacts. Therefore, the operation of the TRTP would not conflict with or obstruct implementation of the applicable air quality plans, and would not have the potential to have considerable incremental effects with cumulative projects relative to conflicts or obstruction of applicable air quality plans. Cumulative impacts would be less than significant. No mitigation measures to address cumulative impacts are required.

Would the proposed Project violate any air quality standards or contribute substantially to an existing or projected air quality violation?

To determine whether implementation of the proposed Project would violate any air quality standards or contribute substantially to an existing or projected air quality violation, a worst-case scenario approach was taken to ensure that all potential air quality impacts are assessed. As such, emissions occurring during peak construction activities were quantified and used to determine air quality impacts. Overall Project construction emissions (i.e., considering overlapping emissions, by air basin, for all applicable TRTP segments) are presented in Table 4.4-30 in Section 4.0; these emissions and associated air quality effects could be exacerbated by emissions from cumulative projects.

As shown in Table 4.4-30, annual construction emissions for the overall TRTP would exceed the AVAQMD’s significance thresholds for NO_X in year 2010 and PM₁₀ in years 2010, 2011, and 2012 and, therefore, would be considered to have significant air quality impacts. Similarly, the comparison of the peak daily construction emissions with the SCAQMD significance thresholds shows that all pollutants exceed the thresholds with the exception of SO₂. The implementation of APMs identified in Section 4.4.5 would reduce overall emissions, but air quality impacts would remain significant and unavoidable during peak year construction in both air basins, although impacts would be short-term. Emissions from the operation of proposed TRTP facilities are considered to be negligible. Hence, the construction of the entire TRTP could potentially contribute to existing violations of O₃ and PM₁₀ air quality standards. Therefore, the construction of the entire TRTP would have a significant impact on air quality. Relative to this CEQA air quality criteria, the proposed TRTP could also be considered to considerably contribute to short term significant cumulative impacts. No feasible mitigation measures have been identified to reduce cumulative impacts to less-than-significant levels.

Would the proposed Project result in a cumulatively considerable net increase of any criteria pollutant for which the Project region is classified as non-attainment under an applicable federal or state AAQS (including releasing emissions which exceed quantitative thresholds for ozone precursors)?

If the Project were to cause annual emissions that exceed the General Conformity Rule (GCR) DeMinimis thresholds, SCE would be required to prepare a comprehensive Air Quality Conformity Analysis and Determination. It should be noted that the GCR DeMinimis thresholds are for the entire air basins and are not for individual air districts. Therefore, to determine conformity requirements for MDAB, construction emissions generated in Kern County (i.e., KCAPCD jurisdiction) are added to emissions generated in northern Los Angeles County (i.e., AVAQMD jurisdiction). Based on the current proposed Project schedule, the maximum annual construction emissions for the proposed Project would occur in 2010 within the MDAB and in the SCAB. Annual construction emissions for year 2010 in the MDAB and the SCAB were compared to their respective GCR DeMinimis thresholds and are provided in Table 4.4-31 in Section 4.0.

The maximum TRTP-specific annual construction emissions generated within the MDAB in year 2010 would be well below the GCR DeMinimis thresholds, and are therefore considered to be consistent with the SIP. However, annual emissions generated during the peak construction year within the SCAB exceed the NO_X thresholds by 9.6 percent and are under the thresholds for all other pollutants. To ensure the proposed Project conformed to the SIP, NO_X emissions would have to be reduced by a minimum of 9.6 percent. It should be noted that Project-specific construction emissions were estimated based on a worst-case scenario (e.g., all construction activities were assumed to overlap throughout the entire year), which is unlikely. NO_X emissions are directly correlated with the number and type of equipment used and operating hours. Based on this consideration, NO_X emissions could be reduced through various methods such as reducing the number of equipment operating at any one time, extending the construction time frame, and/or scheduling of equipment to reduce duplicate equipment operating for the same purpose during the construction phase. The detailed annual emissions calculations and associated assumptions used in the calculations are provided in Appendix G. Given the aforementioned analysis, the proposed TRTP has the potential to result in short-term significant and cumulatively considerable net increases in NO_X emissions with other projects in the SCAB. No feasible mitigation measures have been identified to reduce cumulative impacts to less-than-significant levels.

Would the proposed Project expose sensitive receptors to substantial pollutant concentrations?

Construction activities and associated emissions generated during the various TRTP-specific construction phases could potentially affect sensitive receptors located near the construction zones. The use of construction equipment could create air quality impacts, but with the implementation of the APMs provided in Section 4.4.5 (Section 4.0), Project-specific localized air quality impacts would be expected to be minimal and considered to have a less than significant impact. After construction of the entire TRTP was complete (i.e., in 2013), operational emissions would be generated from the operation of maintenance vehicles driven to the TRTP sites, parked for a short duration, then driven off, and, therefore, would be negligible. Hence, the emissions generated from the construction and operation of the proposed TRTP would not be expected to expose nearby sensitive receptors to substantial pollutant concentrations. The incremental contribution of pollutants from the TRTP on nearby sensitive receptors from a cumulative perspective would not be expected to be considerable or significant. No mitigation measures to address cumulative impacts are required.

Would the proposed Project create objectionable odors that would affect a substantial amount of people?

The use of diesel construction equipment during various construction phases may generate odor that are considered to be a nuisance. Diesel equipment and asphalt paving emit a distinctive odor that may be considered offensive to certain individuals. These odors would be temporary and would not affect a substantial number of people. Therefore, the odor impacts from the proposed TRTP’s construction and operation would be less than significant. The proposed TRTP’s potential odor impacts would be short term, less than significant, and would not be expected to contribute considerably to any potentially significant cumulative odor related impacts in the Project area. No mitigation measures to address cumulative impacts are required.

5.5.4 Biological Resources

The potential for biological impacts of the proposed Project to combine with the effects of other projects within the geographic scope of the cumulative analysis are described below.

5.5.4.1 Cumulative Impact Analysis

5.5.4.1.1 North of ANF. Based on initial assessments of Segments 4, 5, 9, and 10 of the TRTP, the proposed Project would potentially impact sensitive biological resources north of the ANF, including one sensitive habitat, federal- and state-listed and special-status plant and wildlife species (see Sections 4.5.6.1, 4.4.6.2, 4.5.6.6, and 4.5.6.7). These impacts would all be mitigated below a level of significance by incorporating the APMs and biological mitigation measures as described in Section 4.5.5.

Impacts of the cumulative projects on biological resources north of the ANF would occur primarily in undeveloped open space areas and agricultural lands. These projects include wind energy projects, large residential developments, commercial establishments, and associated infrastructure. Those developments and others have the potential to reduce riparian habitat, a community considered to be sensitive by the CDFG, that exist above the Antelope Valley floor in the foothills of the Tehachapi and San Gabriel Mountains. By removal of native plant communities, the projects developed in the uplands and on the Antelope Valley floor would also have the potential to affect 10 special status plants and 23 wildlife species (Tables 4.5-3 and 4.5-4) located within the TRTP study area. These species are distributed within 11 natural plant communities that commonly occur throughout much of the Antelope Valley Region. These projects could cumulatively cause a decline in the abundance of these special-status species, riparian communities, and related sensitive plant and wildlife species supported by these communities resulting in a significant cumulative impact. Most of these projects would independently pass through the CEQA regulatory approval process and would be required to mitigate for significant impacts on sensitive biological resources.

Many of these projects would have potential impacts on the same species as shown in Tables 4.5-3 and 4.5-4 for the TRTP because the plant communities are common to most of the Antelope Valley region. Implementation of the TRTP may potentially affect the special-status species by ground disturbances required for construction of transmission towers, creation of marshalling areas, and clearing of substation sites. Preconstruction or focused surveys would be conducted by the TRTP so that these areas can be avoided to the extent feasible. The TRTP Biological APMs and biological mitigation measures proposed by SCE are expected to reduce impacts to a level below significance for sensitive biological resources in areas north of the ANF. In light of the substantial amount of development expected to occur north of the ANF and based on the wide-spread distribution of the plant communities supporting the sensitive species in the region, any cumulative impacts on these species attributed to the TRTP would be relatively small because of the small amount of ground disturbance that will occur from implementation of the project. The contribution of the TRTP to any cumulative impacts would be less than considerable. No mitigation measures to address cumulative impacts are required.

5.5.4.1.2 ANF. Based on initial assessments, Segments 6 and 11 of the TRTP would potentially impact sensitive biological resources in the ANF including sensitive habitats, federal- and state-listed and Forest Service Sensitive plant and wildlife species, and wetlands, as described in Sections 4.5.6.3 and 4.5.6.8 impacts for Segments 6 and 11. These impacts could all be mitigated below a level of significance by incorporating the proposed APMs and biological mitigation measures described in Section 4.5.5.

mpacts of the cumulative projects within the ANF are limited and include a small wooden bridge for hikers and a redevelopment project that includes new entrance facilities, a two-mile long entrance road, a multi-use trail, a restroom, a maintenance storage building and other related elements. Several resource management projects are also planned, including a fuels management project to reduce the risk of fire in Devil’s Canyon and a restoration and reconstruction project to restore and recover hydrological, biological, cultural, recreational and other values in Rubio Canyon. The ANF may issue Special Use Permits for up to 495 recreational residential units currently or formerly located on 18 tracts of forest land destroyed by wildfires in 2002. The new permits would allow destroyed units to be replaced and existing units to continue to be used for recreational purposes.

The proposed Projects in the ANF could impact sensitive forest, riparian, and wetland habitats and sensitive plant and wildlife species related to those habitats. However, given that the ANF encompasses more than 650,000 acres and based on the protections provided to sensitive resources, regulated and enforced by the USFS, it is unlikely that the cumulative effects of development projects, including the TRTP, would create significant impacts on sensitive biological resources. No mitigation measures to address cumulative impacts are required.

5.5.4.1.3 South of ANF. Based on initial assessments of Segments 7, 8, and 11 of the TRTP would potentially impact sensitive biological resources south of the ANF including sensitive habitats, federal- and state-listed and special-status plant and wildlife species, and wetlands, as described in Sections 4.5.6.4, 4.5.6.5, and 4.5.6.8 impacts for Segments 7, 8 and 11. These impacts could all be mitigated below a level of significance by incorporating the APMs and mitigation measures as described in Section 4.5.5.

Impacts of the cumulative projects south of the ANF would occur primarily in developed or disturbed areas with a low potential for biological resources. Projects with a higher potential to affect biological resources include those developments that extend into open space and impact previously undeveloped habitat such as (potentially) the ones in the Brea, Yorba Linda, and Chino Hills area south of Segment 8, the Whittier Narrows Dam Recreation Area along Segments 7 and 8, the Eaton Canyon area along Segment 11, and the San Gabriel River corridor near the cities of Azusa and Duarte along Segment 7. Those developments, and others, have the potential to reduce sensitive habitats including Coastal Sage Scrub, Riversidian Alluvial Fan Sage Scrub, Native Grasslands, Coast Live Oak and Walnut Woodland, riparian, and wetland habitats. These projects could cumulatively cause a decline in the abundance of those habitats and related sensitive plant and wildlife species. Each of those projects will independently pass through the regulatory approval process and will have to mitigate for significant impacts to sensitive biological resources. The mitigation imposed on independent projects, combined with the implementation of minimization and mitigation measures proposed by SCE would make the TRTP unlikely to produce significant cumulative impacts to sensitive biological resources in areas south of the ANF. No mitigation measures to address cumulative impacts are required.

Would the proposed Project, in combination with other cumulative projects, have a substantial adverse effect on any riparian habitat or other sensitive natural community identified in local or regional plans, policies, regulations or by the CDFG or USFWS?

5.5.4.1.4 North of ANF. The Segments of the proposed TRTP north of the ANF would potentially affect riparian habitat at Anaverde Creek and Amargosa Creek in the foothills north of Vincent Substation. No other sensitive riparian or other sensitive naturally community is present north of the ANF.

The proposed TRTP would span the entire extent of the riparian habitat associated with these two creek crossings, and existing public and access roads would be utilized during construction and operations to avoid new ground-disturbing activities at these creek crossings. The Project would not make an incremental contribution to cumulative impacts on riparian or other sensitive natural communities in the region.

5.5.4.1.5 ANF. The sections of the proposed TRTP within the ANF would potentially impact riparian habitat within Kentucky Springs Canyon Creek, Aliso Canyon Creek, North Fork Mill Creek, Fall Creek, Lynx Gulch Canyon Creek, Upper Big Tujunga Creek, and Cold Springs Canyon and minor stream channels crossed by Segments 6 and 11. Other sensitive habitats that could be impacted by construction operations on Segments 6 and 11 include Coastal Sage Scrub, Riversidian Alluvial Fan Sage Scrub, and Coast Live Oak Woodland. The cumulative projects may be situated such that there is potential for impact to riparian habitats and other sensitive communities including riparian habitat at Littlerock Creek in Cooper Canyon.

The proposed Project would not have a substantial adverse effect on riparian habitat or other sensitive natural communities with the implementation of APMs and biological mitigation measures as described in Sections 4.5.5. Because impacts of the proposed Project are not expected to have a substantial adverse effect, and other proposed projects would require the same level of mitigation to below a level of significance, the cumulative effect of this and other projects would not be expected to be significant. No mitigation measures to address cumulative impacts are required.

5.5.4.1.6 South of ANF. The sections of the proposed TRTP south of the ANF would potentially impact riparian habitat in the vicinity of the Whittier Narrows Dam Recreation Area. Other sensitive natural communities that could be impacted by construction operations on Segments 7, 8, and 11 include Coastal Sage Scrub, Riversidian Alluvial Fan Sage Scrub, and Coast Live Oak and Walnut Woodland, and Native Grasslands. The cumulative projects may be situated such that there is potential for impact to riparian and other sensitive habitats. Riparian habitats occur along Eaton Canyon, San Gabriel River corridor and Whittier Narrows Dam Recreation Area. Riversidian Alluvial Fan Sage Scrub and Coastal Sage Scrub occur within the foothills of the San Gabriel Mountains. The Puente/Chino Hills area contains Coastal Sage Scrub, Coast Live Oak and Walnut Woodland, and Native Grasslands.

The proposed Project would not have a substantial adverse effect on riparian habitat or other sensitive natural communities with the implementation of APMs and mitigation measures as described in Section 4.5.5. Because impacts of this Project would not be expected to have a substantial adverse effect, and other proposed projects would be required to mitigate to below a level of significance, the cumulative effect of this and other projects would not be expected to be significant. No mitigation measures to address cumulative impacts are required.

Would the proposed Project, in combination with other cumulative projects, have a substantial adverse effect, either directly or indirectly or through habitat modifications, on any species identified as a candidate, sensitive, or special-status species in local or regional plans, policies, or regulations, or by the CDFG or USFWS?

5.5.4.1.7 North of the ANF. North of the ANF, TRTP Segments 4, 5, 9, and 10 and many cumulative projects could potentially produce adverse cumulative impacts on the 10 special status plants and 23 wildlife species listed in Tables 4.5-3 and 4.5-4. These species naturally occur in 11 plant communities that are commonly distributed throughout the Antelope Valley region. Special-status species potentially occurring north of the ANF include the Desert Tortoise, Mohave Ground Squirrel, and Burrowing Owl. A substantial amount of acreage that would be affected by the cumulative projects is in areas with plant communities that may support these three species. Permanent cumulative impacts on small areas supporting populations of Desert Tortoise, Mohave Ground Squirrel, and nesting Burrowing Owl in the region may occur during implementation of the TRTP. These impacts will be avoided and mitigated by implementation of the APMs and Biological Mitigation Measures.

The proposed Project would not have a substantial adverse effect on listed species or Critical Habitat for these species with the implementation of TRTP APMs and biological mitigation measures as described in Sections 4.5.5. Because impacts of this Project are not expected to have a substantial adverse effect, and most other proposed projects would be required to mitigate to below a level of significance, the cumulative effect of this and other projects would not be expected to be significant. Given the location of the TRTP and the small amount of permanent ground disturbance that would occur by Project implementation, the Project’s incremental contribution to the cumulative impact on the plant and wildlife species listed in Tables 4.5-3 and Table 4.5-4, would be less than considerable. No mitigation measures to address cumulative impacts are required.

5.5.4.1.8 On the ANF. Sections of Segments 6 and 11 within the ANF would potentially impact species Listed as Endangered, Threatened, or Proposed or Critical Habitat for these species as described in Sections 4.5.6.3 and 4.5.6.8 (Impact sections for Segments 6 and 11). The cumulative projects may be situated such that there is potential for impact to listed species or Critical Habitat for these species. Through the implementation of minimization and mitigation measures, no substantial direct effect on these species or associated Critical Habitat would be expected from construction of Project facilities and infrastructure during implementation of the TRTP. Because impacts of this Project would not be expected to have a substantial adverse effect, and other proposed projects would require the same level of mitigation to below a level of significance, the cumulative effect of this and other projects would not be expected to be significant.

The sections of the proposed TRTP within the ANF would potentially impact special status species and their habitats, as would other planned projects in the area. Through the implementation of minimization and mitigation measures, no substantial direct effect (directly or through habitat modifications) for these species would be expected from construction of Project facilities and infrastructure during implementation of the TRTP. Because impacts of this Project would not be expected to have a substantial adverse effect, and other proposed projects would require the same level mitigation to below a level of significance, the cumulative effect of this and other projects would not be expected to be significant. No mitigation measures to address cumulative impacts are required.

5.5.4.1.9 South of the ANF. The sections of the proposed TRTP south of the ANF would potentially impact species listed as Endangered, Threatened, or Proposed or Critical Habitat for these species as described in Sections 4.5.6.4, 4.5.6.5, and 4.5.6.8 (Impacts Sections for Segments 7, 8, and 11). The cumulative projects may be situated such that there is potential for impact to listed species or Critical Habitat for these species. Listed species potentially occurring in riparian habitats in the Project area south of the ANF include Least Bell’s Vireo, the Southwestern Willow Flycatcher, and the Arroyo Toad. Listed species potentially occurring in Riversidian Alluvial Fan and Coastal Sage Scrub communities include the Coastal California Gnatcatcher. Critical Habitat for the Coastal California Gnatcatcher occurs in the Montebello Hills and the Puente/Chino Hills areas. The Coastal California Gnatcatcher potentially occurs in the foothills of the San Gabriel Mountains and was observed in the Montebello and Puente/Chino Hills areas during investigations for this Project. Removal of riparian or sage scrub communities for this Project and cumulative projects could potentially have a cumulatively significant impact on listed species and Critical Habitats.

The proposed Project would not have a substantial adverse effect on listed species or Critical Habitat for these species with the implementation of APMs and biological mitigation measures as described in Section 4.5.5. Because impacts of the proposed Project would not be expected to have a substantial adverse effect, and other proposed projects would be required to mitigate to below a level of significance, the cumulative effect of this and other projects would not be expected to be significant. No mitigation measures to address cumulative impacts are required.

The sections of the proposed TRTP south of the ANF would potentially impact special-status species and their habitats as described in Sections 4.5.6.4, 4.5.6.5, and 4.5.6.8 (Impact sections for Segments 7, 8, and 11). The cumulative projects may be situated such that there is potential for impacts to special-status species and their habitats. Special-status species potentially occurring in grassland and disturbed areas south of the ANF include the Burrowing Owl. Special-status species potentially occurring in riparian habitats include the Southwestern Pond Turtle. Special-status species potentially occurring in Oak and Walnut Woodlands and along the existing TRTP tower locations include nesting raptors. Permanent impacts to areas with populations of nesting Burrowing Owl, raptors, and Southwestern Pond Turtle during the proposed Project and cumulative projects could potentially have a cumulatively significant impact on special-status species.

Would the proposed Project, in combination with other cumulative projects, have a substantial adverse effect on any federally protected wetlands as defined by Section 404 of the CWA (including, but not limited to, marsh, vernal pool, coastal, etc.) through direct removal, filling, hydrological interruption, or other means?

5.5.4.1.10 North of the ANF. The segments of the proposed TRTP north of the ANF would have no incremental contribution to cumulative impacts to federally protected wetlands. No mitigation measures to address cumulative impacts are required.

5.5.4.1.11 On the ANF. The sections of the proposed TRTP within the ANF would potentially impact federally protected wetlands, as would other planned projects in the area. Through the implementation of APMs and mitigation measures, no substantial direct effect on federally protected wetlands would be expected from construction of Project facilities and infrastructure during implementation of the TRTP. Because impacts of this Project are not expected to have a substantial adverse effect, and other proposed Projects would require the same level mitigation to below a level of significance, the cumulative effect of this and other projects would not be expected to be significant. No mitigation measures to address cumulative impacts are required.

5.5.4.1.12 South of the ANF. The sections of the proposed TRTP south of the ANF and the other cumulative projects would potentially impact federally protected wetlands. Through the implementation of APMs and biological mitigation measures as described in Section 4.5.5, no substantial direct effect on federally protected wetlands would be expected from construction of Project facilities and infrastructure during implementation of the TRTP. Because impacts of this Project would not be expected to have a substantial adverse effect, and other proposed projects would be required to mitigate to below a level of significance by federal and state regulations, the cumulative effect of this and other projects would not be expected to be significant. No mitigation measures to address cumulative impacts are required.

Would the proposed Project, in combination with other cumulative projects, interfere substantially with the movement of any native resident or migratory fish or wildlife species or with established native resident or migratory wildlife corridors, or impede the use of native wildlife nursery sites?

5.5.4.1.13 North of the ANF. The cumulative projects are distributed within the various common plant communities of the region. Because the number of identified projects is large, and because many of them are large in scale, some of the projects in the region are reasonably expected to incrementally cause significant cumulative impacts on movements of wildlife by removal of plant communities that support daily and seasonal movements of wildlife and plant populations. The TRTP transmission corridor would, however, provide unimpeded open space across the Antelope Valley floor between the Vincent Substation and the terminus of both Segments 4 and 10. The TRTP would not block movement of native resident or migratory species in any cardinal direction, nor would it impede the use of native wildlife nursery sites. Any interruption of native wildlife movement during construction activities would be temporary and minor in extent. Given the non-intrusive nature of the TRTP facilities (towers and substations), the proposed Project would not interfere substantially with the movement of any resident or migratory species. The TRTP would have a less than considerable cumulative impact on the movement of resident or migratory fish or wildlife species. No mitigation measures to address cumulative impacts are required.

5.5.4.1.14 On the ANF. The sections of the proposed TRTP within the ANF and the cumulative projects would not be expected to significantly impact wildlife movement and would not significantly add to the cumulative impacts in the region. No mitigation measures to address cumulative impacts are required.

5.5.4.1.15 South of the ANF. The sections of the proposed TRTP south of the ANF and the cumulative projects would not be expected to significantly impact wildlife movement and would not significantly add to the cumulative impacts in the region. No mitigation measures to address cumulative impacts are required.

Would the proposed Project, in combination with other cumulative projects, conflict with any local policies or ordinances protecting biological resources, such as tree preservation policy or ordinance?

5.5.4.1.16 North of the ANF. The proposed TRTP corridor crosses two Los Angeles County Significant Ecological Areas (SEAs) that are designated to protect a suite of plant communities and species. CPUC General Order 131-D preempts local jurisdictions from regulating electric power line projects. However, any areas of the TRTP passing through the SEAs where there may be protected candidate, sensitive, or special-status species would be avoided to the extent feasible. If any special-status species is located in areas that cannot be avoided during construction, the implementation of APMs and biological mitigation measures outlined in Section 4.5.5 would ensure that this impact would not conflict or have an adverse cumulative effect on the biological resources protected by the SEAs. Other cumulative projects that may be built in the SEAs generally would be subjected to a CEQA-level review by the Significant Ecological Areas Technical Advisory Committee prior to their implementation, and would be mitigated to a level below significance. The TRTP APMs and mitigation measures are consistent with SEA policies and ordinances protecting biological resources within the SEAs. The TRTP would make a less than considerable incremental contribution to cumulative impacts on local policies or ordinances protecting biological resources. No mitigation measures to address cumulative impacts are required.

5.5.4.1.17 On the ANF. The proposed Project and the cumulative projects would not conflict with local policies or ordinances protecting biological resources. The Project mitigation measures are consistent with USFS policies and ordinances protecting biological resources. Significant cumulative impacts would therefore not occur. No mitigation measures to address cumulative impacts are required.

5.5.4.1.18 South of the ANF. The proposed Project would not conflict with local policies or ordinances protecting biological resources such as local Oak and Walnut Woodland ordinances. The proposed Project mitigation measures are consistent with local policies and ordinances protecting biological resources. Therefore, significant cumulative impacts would not occur. No mitigation measures to address cumulative impacts are required.

Would the proposed Project, in combination with other cumulative projects, conflict with the provisions of an adopted Habitat Conservation Plan, Natural Communities Conservation Plan, or other approved local, regional, or state habitat conservation plan?

5.5.4.1.19 North of the ANF.The TRTP north of the ANF passes through the western-most portion of the West Mojave Plan (WMP), a federally-approved Habitat Conservation Plan to conserve and protect the Mohave Ground Squirrel and Desert Tortoise, plus 100 other sensitive species. The WMP applies only to projects under federal jurisdictions, and is not applicable to private lands on which the TRTP is proposed. Projects developed in the area west of Highway 14 may have an adverse incremental cumulative impact on Desert Tortoise and Mohave Ground Squirrels. These two species are considered to be present in very low densities west of Highway 14 (1 to 20 individuals per square mile). The northern half of the NPPSA passes through a WMP “Survey Area” that designates preconstruction clearance surveys for Desert Tortoises in areas where Project ground disturbances may occur. The southern half of the NPPSA is within a “No Survey” area. The range of the Mohave Ground Squirrel occurs on the Antelope Valley floor to the east of the TRTP, approaching within 3 miles of the TRTP transmission corridor at its closest, where no habitat for the species is present along the transmission corridor. The Mohave Ground Squirrel habitat is 5 miles east of the northern terminus of Segment 10, and does not require CDFG surveys at that distance from the currently documented boundary. The TRTP would conduct preconstruction surveys for the Desert Tortoise and Mohave Ground Squirrel. If any Desert Tortoise or Mohave Ground Squirrels are located in areas where TRTP ground disturbances would occur, the implementation of APMs and biological mitigation measures outlined in Section 4.5.5 would ensure that any Project-related disturbances will not have a substantial adverse effect on these species. Given the location of the TRTP and the small amount of permanent ground disturbance that would occur by Project implementation, the Project’s incremental contribution to the cumulative impact on Desert Tortoise and Mohave Ground Squirrel would be less than considerable. Further, given that there is not an adopted HCP or NCCP within the private lands traversed by the TRTP, implementation of the TRTP would have no incremental contribution to cumulative impacts to provisions in an adopted HCP or NCCP. No mitigation measures to address cumulative impacts are required.

5.5.4.1.20 On the ANF. This section of the proposed Project and the cumulative projects lie within the ANF and there is not an adopted HCP or NCCP within the Project area, therefore, cumulative impacts related to an adopted HCP or NCCP would not occur. No mitigation measures to address cumulative impacts are required.

5.5.4.1.21 South of the ANF. There is not an adopted HCP or NCCP within this section of the proposed Project, and cumulative impacts would not occur. No mitigation measures to address cumulative impacts are required.

5.5.5 Cultural Resources

The geographic extent for the analysis of cumulative impacts to Cultural Resources is defined generally as a 10-mile-wide corridor with the proposed Project T/L route(s) at the center. Patterns of development illustrated on Figure 5.3-1 [Sheet 1, 2] and summarized in Tables 5.3-1 and 5.3-2 indicate that more than 165,000 acres of land within the corridor are likely to be developed over the next several decades. Much of the development would consist of large-scale residential and commercial projects that would collectively result in the construction of more than 60,000 homes. The spatial pattern of development indicates that cumulative impacts can be described in terms of three fairly distinct areas that exhibit different geographic and jurisdictional characteristics that affect the nature, type and intensity of development. These three areas include lands north of the ANF, the ANF, and lands south of the ANF (see Figure 5.3-1 [Sheet 1, 2] ).

5.5.5.1 Cumulative Impact Analysis

This section evaluates the potential for the TRTP to have cumulative impacts to archeological and historical resources. Issues related to unique geological features and paleontological resources are addressed in Sections 5.5.6 and 5.5.17, respectively. Cultural resource issues of concern relative to potential cumulative impacts are addressed below.

Would the proposed Project, in combination with other cumulative projects, cause a substantial adverse change in the significance of a historical resource, an archaeological resource, a historic property, or disturb any human remains?

The following discussion, as indicated above, is organized geographically.

5.5.5.1.1 North of the ANF. The area north of the ANF is located within the western portion of the Mojave Desert and is roughly bounded on the north by the Tehachapi Mountains and on the south by the Transverse Ranges. In between lays the large, relatively flat landform known as the Antelope Valley. Much of this area is undeveloped, available, and relatively inexpensive. As a result, many past, current and future projects in this area are large in scale. These include at least five wind energy projects in the Tehachapi area, the largest of which include the 32,000-acre Alta Wind Energy Center Project, the 8,000-acre Pine Tree Wind Project, and the 6,400-acre PdV Wind Energy Project. Other large projects in the Antelope Valley include large residential developments that would construct up to 29,000 residential units, commercial establishments, and associated infrastructure on approximately 24,000 acres of land in southern Kern County and in undeveloped portions of Lancaster and Palmdale in northern Los Angeles County (see Figure 5.3-1 [Sheet 1, 2] ). The largest example of this type of development is the Ritter Ranch Master Planned Community located in the hills above Palmdale. This large development would impact approximately 11,520 acres of undeveloped land and eventually will include over 7,000 homes, seven schools, a golf course, and approximately 75 acres of commercial development.

Grading and other ground-disturbing activities associated with cumulative developments in this northern area would be expected to disturb and destroy cultural resources. Although the total number of cultural resources that may be impacted as a result of development is unknown, a rough order of magnitude estimate can be derived from intensive surveys conducted for the TRTP and the Pine Tree Wind Energy Project. Intensive survey of the 8,000-acre Pine Tree Project site yielded 90 prehistoric and historic sites (LADWP and BLM, 2004) while the intensive cultural resource survey of TRTP Segments 4, 5 and 10 located a total 34 sites. Site densities in the four survey areas varied from 5.0 to 23.6 sites per square mile and averaged 8 sites per square mile. In terms of size, cumulative projects in undeveloped areas are dominated by wind farms (48,000 acres) and large-scale planned residential developments (24,000 acres) near Mojave, Palmdale, and Lancaster. Some areas have been affected by agriculture but most of these 72,000 acres have not been previously developed and could contain cultural resources. Based on an average of 8 sites per square mile, the wind farms and planned residential development project areas could include approximately 900 cultural resources. How many would be directly affected by development is unknown but the scale and nature of the projects can be used to generate an order of magnitude estimate. Large-scale residential and commercial developments, for example, would be expected to disturb or destroy a relatively high proportion of sites within their development footprint, perhaps as high as 90 percent. In contrast, wind farms might be expected to affect lower proportions due to some flexibility in turbine placement. The Pine Tree Wind Development Project, for example, is expected to affect only 22 percent of the sites within its footprint (LADWP and BLM, 2004: 3.8-11).

Based on such figures, development of wind farms and large-scale residential developments north of the ANF could disturb or destroy on the order of 400 cultural resource sites, some, if not many, of which would be expected to meet criteria as unique archaeological resources, historical resources or as historic properties. An unknown but relatively small number would have a reasonable potential to contain human remains. The 400-site figure does not take into consideration that some of the lands have been previously disturbed but, on the other hand, the figure also does not include estimated impacts from other types of development expected to occur in the area. As a result, the estimate that roughly 400 sites could be affected by cumulative development north of the ANF is considered a reasonable approximation.

The vast majority of the cumulative projects would likely undergo CEQA and/or NEPA review and unavoidable sites would be tested to evaluate significance and significant sites would be subject to historical documentation or data recovery excavations to mitigate impacts. Although these measures would reduce most individual site impacts to less than significant levels, archaeological excavation and analysis cannot recover all the scientific values of a site. Based on the above, the cumulative loss of approximately 400 archaeological and historical sites in the Antelope Valley and adjacent areas is considered a significant impact that cannot be mitigated to less than significant levels. However, intensive survey of TRTP proposed Segments 4, 5, and 10 indicates that the TRTP’s contribution to this cumulative impact would not be “considerable.” Although a total of 34 sites were identified in the TRTP T/L right-of-way (R‑O‑W), the nature of the Project suggests that most of these sites could be avoided by proper siting of towers, access and spur roads, staging areas, and other project components. Sites avoided by the TRTP would also be protected from other projects as well, since SCE does not allow other project construction within its T/L R‑O‑Ws. No mitigation measures to address cumulative impacts are required.

5.5.5.1.2 On the ANF. TRTP Segments 6 and 11 traverse rugged, mountainous terrain and deeply incised drainages and canyons as they cross the ANF. Not surprisingly, development on the forest is limited and includes only a few scattered construction projects. These include a small wooden bridge for hikers and a redevelopment project that includes new entrance facilities, a 2-mile long entrance road, a multi-use trail, a restroom, a maintenance storage building and other related elements. Several resource management projects are also planned, including a fuel management project to reduce the risk of fire in Devil’s Canyon and a restoration and reconstruction project to restore and recover hydrological, biological, cultural, recreational and other values in Rubio Canyon. Finally, the ANF may issue Special Use Permits for up to 495 recreational residential units currently or formerly located on 18 tracts of forest land. Many of these residences were destroyed by wildfires in 2002. The new permits would allow destroyed units to be replaced and existing units to continue to be used for recreational purposes. Given that the ANF encompasses more than 650,000 acres, cultural resource impacts from the TRTP and the projects noted above would not be cumulatively considerable. No mitigation measures to address cumulative impacts are required.

5.5.5.1.3 South of the ANF. Most cumulative projects in the area south of the ANF would occur in urbanized areas with a low potential for cultural resources. Projects with a higher potential to affect cultural resources include several relatively small planned residential developments in the Duarte-Azusa area just south of the ANF and eight large planned residential developments in the vicinity of Brea, Yorba Linda, and Chino. The Duarte-Azusa developments are relatively small-scale and are not located in areas of high cultural resource sensitivity (survey of Segment 7 identified only one small prehistoric lithic scatter, a historic dirt road and a historic dam). The eight other planned developments are much larger and would encompass more than 19,000 acres and result in the construction of more than 30,000 homes. For the most part these project areas consist of narrow, steep-sided hills that would not be expected to contain many sites and cumulative impacts south of the ANF are not expected to be considerable. The TRTP survey of Segment 8 located only six sites, which represents an archaeological density of only 1.4 sites per square mile. This low figure undoubtedly reflects that urban development has destroyed most of the archaeological resources in this area. In terms of impacts, most if not all of these sites can be expected to be avoided. In sum, neither the TRTP nor other developments south of the ANF are likely to have a considerable cumulative impact on the regional archaeological record. No mitigation measures to address cumulative impacts are required.

5.5.5.1.4 Summary. Cumulative development north of the ANF is expected to have a significant, unmitigatable impact on cultural resources in the region. However, as a result of implementation of SCE Applicant Proposed Measures (APMs), the Project’s incremental contribution to cumulative impacts to cultural resources would not be cumulatively considerable. No mitigation measures to address cumulative impacts are required.

5.5.6 Geology and Soils

The geographic extent for considering cumulative impacts to geology and soils is limited to the immediate vicinity of the TRTP T/L R‑O‑Ws, and substation construction and expansion areas (Whirlwind, Antelope, and Vincent substations). The “immediate vicinity” includes the area physically within the R‑O‑W, as well as areas outside the R‑O‑W which may be occupied during construction or operation of the Project for project-related uses. This geographic extent is appropriate for the geology and soils issue area because any potential impacts of the proposed Project would be site-specific.

5.5.6.1 Cumulative Impact Analysis

Past and ongoing development throughout the proposed TRTP Project area has resulted in substantial alterations to the natural landscape. In order to be cumulatively considerable, impacts to geology and soils would have to occur at the same time and in the same location as the proposed Project. Seismic impacts (ground shaking, earthquake-induced ground failure, and fault rupture) from the numerous local and regional faults comprise an impact of the geologic environment on individual projects and would not introduce cumulatively considerable impacts. No mitigation measures to address cumulative impacts are required.

The discussion below considers whether the cumulative projects and the TRTP would have a cumulatively significant impact on geology and soils and whether the TRTP’s contribution to those impacts would be cumulatively considerable.

Would the proposed Project, in combination with other cumulative projects, expose people or structures to potential substantial adverse effects, including the risk of loss, injury, or death, involving rupture of a known earthquake fault?

The proposed Project would not increase the exposure of people to earthquake faults. Structures associated with the proposed Project would cross known earthquake faults along Segments 5, 6, 7, and 8. However, SCE proposes to conduct a geotechnical study, which would identify site-specific geologic conditions and potential geologic hazards. Results of the study would be incorporated into final design. Such design parameters would minimize potential effects resulting from the proposed Project in the event of the rupture of a known fault.

It is not expected that impacts of any other projects would combine with potential impacts of the proposed Project in a way that would increase the potential for Project T/Ls to be damaged by these forces. There would be no cumulative impact and therefore, no mitigation measures to address cumulative impacts are required. No mitigation measures to address cumulative impacts are required.

Would the proposed Project, in combination with other cumulative projects, result in cumulative impacts from fault ruptures, seismic events, landslides, earth flows, debris slides, ground shaking, or corrosive soils?

It is not expected that impacts of any other projects could combine with potential impacts of the proposed Project in a way that would increase the potential for Project T/Ls to be damaged by these forces. There would be no cumulative impact and therefore, no mitigation measures to address cumulative impacts are required.

Would the proposed Project, in combination with other cumulative projects, result in substantial soil erosion or the loss of topsoil?

Portions of all of the Segments within the TRTP route are underlain by soils classified as having moderate to severe hazard of erosion on roads and trails. Areas of greatest soil erosion potential are present in the steeply sloping terrain of the Transverse Ranges in Segments 6, 7, and 11 on and immediately south of the ANF. Construction of the proposed Project and other cumulative projects could trigger or accelerate soil erosion through land disturbance activities. These impacts of the proposed Project would be minimized through implementation of APM GEO-3, which specifies preparation and implementation of a Construction SWPPP. A Construction SWPPP would be required for all construction projects that disturb one or more acre of ground surface. Therefore, any other project which could potentially introduce similar erosion events also would be required to minimize such impacts through compliance with a Construction SWPPP.

Finally, it is not expected that other projects would be constructed in the same places and at the same times as the proposed Project. As a result, there would be no cumulative impact, and therefore, no mitigation measures to address cumulative impacts are required.

Would the proposed Project, in combination with other cumulative projects, be located on a geologic unit or soil that is unstable, or that would become unstable as a result of the project, and potentially result in onsite or offsite landslide, lateral spreading, subsidence, liquefaction, or collapse?

Due to the presence of landslide-prone geologic units in the Project area, slope instability could potentially be caused if excavation or grading for another project occurs immediately near (in distance and time) similar activities for the proposed Project. However, in accordance with TRTP APM GEO-2, SCE would conduct geotechnical studies to avoid and minimize potential impacts from geologic hazards or soil conditions. Also, SCE generally does not allow other projects to construct in its R‑O‑Ws and would not allow activity that could threaten the TRTP T/L. Because excavation and grading for multiple projects are not expected to occur in the exact location at the exact same time as the TRTP, there would be no cumulative impact, and therefore, no mitigation measures to address cumulative impacts are required.

Would the proposed Project, in combination with other cumulative projects, be located on expansive soil and create substantial risks to life or property?

While the likelihood of expansive soils occurring would not be high, given the geologic conditions along the proposed Project area, such soils could still be encountered in localized areas. As previously discussed, APM GEO-2 would identify site-specific geologic conditions and hazards such as expansive soils and provide engineering design and construction recommendations to avoid and minimize potential impacts. Because excavation and grading for multiple projects are not expected to occur in the exact location at the exact same time as the TRTP, there would be no cumulative impact, and therefore, no mitigation measures to address cumulative impacts are required.

Would the proposed Project, in combination with other cumulative projects, have soils incapable of adequately supporting the use of septic tanks or alternative waste water disposal systems where sewers are not available for the disposal of waste water?

The proposed Project would not involve the use of septic tanks or alternative waste water disposal systems. As a result, there would be no cumulative impact, and therefore, no mitigation measures to address cumulative impacts are required.

5.5.7 Hazards and Hazardous Materials

The geographic extent for the analysis of cumulative impacts related to hazards and hazardous materials, including impacts to soil and groundwater, is limited to the immediate vicinity surrounding the TRTP R‑O‑Ws and substations. The potential release of hazardous materials resulting from the proposed Project activities would be site-specific to the actual release location or location of impacted soil or groundwater. The potential of a release to migrate offsite would be addressed by compliance with appropriate federal, State, and local regulations as discussed in Section 4.8 and Appendix K.

The area along the proposed Project T/L alignments north of the ANF primarily consists of undeveloped and open space land, scattered rural residences, and new residential developments. No known impacted soils or groundwater exist along the proposed Project alignment. The project routes on the ANF are restricted to existing utility corridors are also unlikely to have impacts to soil or groundwater. Based on this mix of non-hazardous land uses along the Project alignment, there is a low likelihood of significant existing unknown impacts to soil or groundwater in these areas. The TRTP routes south of the ANF include a mix of highly urbanized areas and previously undeveloped and/or vacant lands and have a higher potential to contain impacted soil or groundwater. There is a possibility that impacts to soil or groundwater may exist at properties located within the immediate vicinity or adjacent to the proposed Project R‑O‑W. Phase I Environmental Site Assessments as described in APM HAZ-1 would likely identify these properties prior to construction or operation or the proposed Project. Therefore, the potential for offsite facilities to directly affect the proposed Project is low.

5.5.7.1 Cumulative Impact Analysis

The following analysis evaluates whether the proposed Project has the potential to cause cumulative impacts to hazards and hazardous materials. Specific issues addressed in the analysis include the following:

Would the proposed Project, in combination with other cumulative project, create a significant hazard to the public or the environment through the routine transport, use, or disposal of hazardous materials?

A wide variety of regulatory controls exist to ensure safe handling, storage, transport, disposal, and treatment of hazardous materials and hazardous waste in California (see Section 4.8 and Appendix K). In accordance with these regulatory controls, SCE has identified APMs that would minimize the potential creation of hazards or release of hazardous materials such that the proposed Project would not result in a cumulatively considerable impact. These APMs include HAZ-1 (conduct Phase I Environmental Site Assessments), HAZ-2 (implement a series of actions designed to appropriately manage hazardous materials and hazardous waste, including the preparation and implementation of a SWPPP), HAZ-3 (preparation of a Soil Management Plan to ensure proper handling, onsite management, and disposal of impacted soil that may be encountered), HAZ-4 (implement Fire Management Plan), and HAZ-5 (prepare or update a Spill Prevention, Countermeasure, and Control Plan [SPCC] and a Hazardous Materials Business Plan for applicable substations in accordance with the California Health and Safety Code and Title 22 of the California Code of Regulations).

Cumulative impacts would only be considered significant if concurrent construction of the proposed Project and other local projects would result in the use and/or transport of large volumes of hazardous materials thereby creating a potential hazard, or if significant volumes of impacted soil would be generated requiring offsite treatment. Construction and operation of the proposed TRTP would involve only minor quantities of hazardous materials (e.g., fuel, lubricants, paint, etc.) and no cumulative projects have been identified that would involve the use or transport of large quantities of hazardous materials. Based on the largely rural character of the ANF and Project areas to the north, no significant quantities of impacted soil are expected to be encountered or generated during construction of the proposed Project. Moreover, other projects would be subject to the same regulatory controls as SCE and are expected to implement measures similar to the TRTP APMs. Therefore, no cumulative impacts involving hazardous materials and hazardous wastes are expected. No mitigation measures to address cumulative impacts are required.

Would the proposed Project, in combination with other cumulative projects, create a significant hazard to the public or the environment through reasonably foreseeable upset and accident conditions involving the release of hazardous materials in the environment?

As discussed above, a wide variety of regulatory controls exist to ensure safe handling, storage, transport, disposal, and treatment of hazardous materials and hazardous waste in California (see Section 4.8 and Appendix K). In accordance with these regulatory controls, SCE has identified APM HAZ-2 for hazardous materials and waste handling management and APM HAZ-5 for implementation of SPCC Plans and Hazardous Materials Plans where applicable, to prevent releases of hazardous materials. If in the case of a potential release, procedures implemented through the SPCC, Hazardous Material Business Plans, and Emergency Release Response Procedures (APM HAZ-2) would manage, control, and minimize the release to the extent that the TRTP’s incremental contribution to the cumulative impact would not be cumulatively considerable. No mitigation measures to address cumulative impacts are required

Would the proposed Project, in combination with other cumulative projects, emit hazardous emissions or handle hazardous or acutely hazardous materials, substances, or waste within one-quarter mile of an existing or proposed school?

The proposed Project would not involve the use or emission of hazardous or acutely hazardous materials, substances, or wastes within 0.25 mile of an existing or proposed school. For this reason, the proposed Project would have no cumulative impact with respect to such releases. No mitigation measures to address cumulative impacts are required.

Would the proposed Project, be located on a site which is included on a list of hazardous materials sites, and as a result, in combination with other cumulative projects, create a significant hazard to the public or the environment?

Soil and groundwater in the area of the proposed Project have the potential to be adversely impacted by hazardous materials and wastes from past activities at properties within, adjacent, or near the proposed Project. If impact solid or groundwater were encountered and were not properly managed, this could potentially result in exposure of construction workers and the community to potential health hazards and further degradation of the environment. As a result, SCE proposes to implement APM HAZ-1 to conduct a Phase I Environmental Site Assessment (ESA) to identify potential contaminated areas and APM-HAZ-3 to prepare and implement a Soil Management Plan, which would provide guidance on proper handling, onsite management, and disposal of impacted soil which may be encountered during construction. Appropriately trained professionals would be onsite during preparation, grading, and related earthwork activities to monitor soil conditions. In this way, the proposed Project’s implementation of APM HAZ-1 and APM HAZ-3 would minimize the potential incremental contribution of hazards to the public and environment, and the TRTP’s incremental contribution to the cumulative impact would not be cumulatively considerable. No mitigation measures to address cumulative impacts are required

Would the proposed Project, be located within an airport land use plan or, where such a plan has not been adopted, within two miles of a public airport or public use airport or a private airstrip, such that the project, in combination with other cumulative projects, would result in a safety hazard for people residing or working in the project area?

The proposed Project is located within areas covered by airport land use plans and within 2 miles of public airports, but would not result in a safety hazard because SCE would be required to consult with the FAA and conform to all applicable FAA safety standards and guidelines. As a result, the proposed Project would have no cumulative impact on airport safety. No mitigation measures to address cumulative impacts are required.

Would the proposed Project, in combination with other cumulative projects, impair implementation of or physically interfere with an adopted emergency response plan or emergency evacuation plan?

During construction, all activity would occur on the proposed Project site; however, in the event an activity is planned that could potentially affect implementation of an emergency response plan or emergency evacuation plan, SCE would consult with local agencies including Caltrans, in order to determine an acceptable traffic system or alternative route, if needed. Therefore, the proposed Project would not impair implementation of or physically interfere with an adopted emergency response plan or emergency evacuation plan. In addition, other cumulative projects are expected to implement similar measures and no significant cumulative impacts are expected. No mitigation measures to address cumulative impacts are required.

Would the proposed Project, in combination with other cumulative projects, expose people or structures to a significant risk of loss, injury, or death involving wildland fires, including where wildlands are adjacent to urbanized areas of where residences are intermixed with wildlands?

During construction, the risk of fire danger from a project would be related to smoking, refueling and operating vehicles and other equipment off roadways. T/Ls may pose a low risk of if a conducting object comes in close proximity of a line or if a line falls to the ground.

SCE proposes APM HAZ-4 to develop and implement a Fire Management Plan (included as Appendix D in this PEA). The Fire Management Plan addresses construction activities for the Project, and establishes standards and practices that will minimize the risk of fire danger, and in the case of fire, provide for immediate suppression and notification. Areas of highest sensitivity are located on the ANF where future cumulative developments are relatively small scale and few in number. The ANF and other jurisdictions would require the cumulative projects to implement appropriate procedures to avoid and minimize the potential for wildland fires, and, as a result, the potential for cumulative projects to cause significant risk of loss, injury, or death from wildfire during construction is considered low. For these reasons, the cumulative impact would be less than significant. No mitigation measures to address cumulative impacts are required

During operation, T/Ls may pose a low risk of fire if a conducting object comes in close proximity of a line or if a line falls to the ground. However, T/L structures used to support overhead T/Ls must meet the requirements of the California Public Utility Commission, General Order No. 95, Rules for Overhead Electric Line Construction and other applicable regulations, including the National Electric Safety Code. Because the proposed Project incorporates system protection features designed to safeguard the public and Project components, and all other cumulative projects are expected to comply with existing safety codes and regulations, the cumulative potential to cause significant risk of loss, injury, or death from wildfire due to design-related problems is considered low. Given that the cumulative projects are not expected to pose a significant risk of fire, and given that SCE is committed to implementing its Fire Management Plan, the TRTP’s contribution to regional fire risk would not be cumulatively considerable. No mitigation measures to address cumulative impacts are required.

Maintenance vehicles may pose as a fire risk if sparks from the exhaust ignite nearby brush. However, SCE will maintain appropriate vegetation clearance during construction and operation of the Project to reduce the fire hazard potential. Additionally, APM HAZ-4 mentioned above, also consists of an operation component, which addresses operation and maintenance-related standards and practices which will minimize the risk of fire danger, and in the case of fire, provide for immediate suppression and notification. With implementation of the measures presented in APM-HAZ-4, the proposed Project’s incremental contribution to wildfire hazards from maintenance activities would not be cumulatively considerable. No mitigation measures to address cumulative impacts are required.

5.5.8 Hydrology and Water Quality

The geographic scope of cumulative effects for hydrology and water quality includes the area encompassed by the combined boundaries of the 14 Hydrologic Sub-Areas (HSAs) traversed by the proposed Project. HSAs are typically similar in geology and hydrology. HSA boundaries are appropriate to represent the geographic extent of this cumulative effects analysis because their combined area includes all major hydrologic features that could be directly affected by the proposed Project.

5.5.8.1 Cumulative Impact Analysis

Hydrological and water quality impacts of the TRTP would be less than significant with implementation of the APMs detailed in Section 4.9 (see Table 4.9-1). These include APM HYD-1 (Develop and Implement a Construction SWPPP), APM HYD-2 (Conduct an Environmental Training Program), APM HYD-3 (Establish Accidental Spill Control Procedures), APM HYD-4 (Establish Non-storm Water and Waste Management Pollution Controls), APM HYD-5 (Conduct Phase 1 ESAs), APM HYD-6 (Implement Construction Site Dewatering Procedures), APM HYD-7 (Design and Site Structures to Avoid and Minimize Flood Damage), and APM HYD-8 (Operation Storm Water Management Plan).

The paragraphs that follow summarize Project impacts and assess whether they would be considerable when combined with other past, present and foreseeable projects.

Would the proposed Project, in combination with other cumulative projects, violate any water quality standards or waste discharge requirements?

Soil disturbance during the construction of any project can result in soil erosion and sedimentation that can affect water quality. Most soil disturbance by the TRTP would occur during construction of temporary and permanent roads, as well as substation construction (Whirlwind) and expansions (Antelope and Vincent). These activities involve soil disturbance and stockpiling of earth that could potentially accelerate erosion that could wash into waterways and downstream tributaries. Implementation of APM HYD-1 (Develop and Implement a Construction SWPPP) and APM HYD-2 (Conduct an Environmental Training Program) would reduce these impacts to less than significant levels. Moreover, projects that would disturb one or more acres of ground surface also would need to implement a Construction SWPPP to control erosion. Although proposed Project impacts could combine with other construction projects in the same watersheds, the incremental contribution of the proposed Project would not be considerable when compared to the scale of the cumulative projects. No mitigation measures to address cumulative impacts are required.

Water quality can also be affected by accidental release of hazardous materials during any construction project. Such materials include: diesel fuel, gasoline, lubricant oils, hydraulic fluid, antifreeze, transmission fluid, lubricant grease, and other fluids. The preparation and pouring of concrete and the use of motorized equipment are examples of construction activities that would specifically involve the use of potentially harmful materials. The release of one or more hazardous materials could occur at tower installation locations, site laydown and preparation areas, substations, and other locations where construction activities would occur. Accidentally spilled hazardous materials could pollute surface water through direct runoff into nearby waterways or water bodies, including ephemeral streams and desert washes. These materials could also pollute groundwater through soil infiltration or direct runoff, if the groundwater table is exposed during excavation activities and such activities coincide with the occurrence of an accidental spill. Any of the waterways traversed by the proposed Project could be affected by this impact. In addition, tributaries of these waterways could also be affected, depending on the severity of the spill.

To reduce potential impacts to water quality from accidental releases of hazardous materials, SCE would implement APM HYD-1 through APM HYD-4, which consists of: Storm Water Pollution Prevention Plan(s) (SWPPP), Environmental Training Program, Accidental Spill Control Procedures, and Non-Storm Water and Waste Management Pollution Controls. Such measures would manage, control, and minimize potential water contamination such that the proposed Project’s incremental contribution to cumulative impacts would be less than considerable. No mitigation measures are required.

Would the proposed Project, in combination with other cumulative projects, substantially deplete groundwater supplies or interfere substantially with groundwater recharge such that there would be a net deficit in aquifer volume or a lowering of the local groundwater table level?

The TRTP has the potential to encounter groundwater during drilling and excavation of footing for LSTs and TSPs. The small size of each footing and the dispersed spatial distribution of the footings indicate the proposed Project would not substantially deplete or impact groundwater supplies or substantially interfere with recharge. The TRTP would introduce only minor amounts of new permanent impervious areas. Compared with cumulative residential developments that would greatly increase water use and create thousands of acres of new impermeable surfaces throughout the Antelope Valley, the proposed Project’s incremental contribution to the cumulative impact would not be considerable. No mitigation measures to address cumulative impacts are required.

Would the proposed Project, in combination with other cumulative projects, substantially alter the existing drainage pattern of the site or area, including through the alteration of the course of a stream or river, in a manner which would result in substantial erosion or siltation onsite or offsite or substantially increase the rate or amount of surface runoff in a manner which would result in flooding onsite or offsite?

The LSTs and TSPs would not be located in a streambed or riverbed and therefore there would be little or no potential for the proposed Project to alter the course of such watercourses. Scraping and grading for the towers and new spur and access roads would remove vegetation and disturb the soil surface, which would result in a negligible reduction in the infiltration and absorption capacity of surface soils within the impacted area. The potential impacts from spur roads and access roads would be localized and temporary. In addition, the SWPPP required by APM HYD-1 would include an erosion control plan to minimize any potential increase in surface water runoff resulting from new or improved roads. As a result, the proposed Project’s incremental contribution to these cumulative impacts would not be considerable. No mitigation measures to address cumulative impacts are required.

Would the proposed Project, in combination with other cumulative projects, create or contribute runoff water which would exceed the capacity of existing or planned stormwater drainage systems or provide substantial additional sources of polluted runoff?

The potential runoff from towers is expected to be negligible due to the small surface area of each footing. In addition, towers would be designed and engineered to facilitate natural drainage patterns. As a result, the proposed Project’s incremental contribution with respect to runoff would be less than cumulatively considerable. No mitigation measures to address cumulative impacts are required.

Would the proposed Project, in combination with other cumulative projects, place housing within a 100-year flood hazard area?

The proposed Project does not involve housing construction and would have no cumulative impact in this regard. No mitigation measures to address cumulative impacts are required.

Would the proposed Project, in combination with other cumulative projects, place within a 100-year flood hazard area structures which would impede or redirect flood flows?

The proposed Project would locate some LSTs within some FEMA-designated Flood Hazard Areas. Development is permitted in Flood Hazard Areas, provided that the development complies with local floodplain management ordinances. Due to the relatively small size of LSTs and TSPs and their dispersed siting, placement of towers in Flood Hazard Areas is not expected to cause diversion of flows or increased flood risk for adjacent property. All applicable floodplain management ordinances would be fully complied with in accordance with FEMA’s regulations on development in Flood Hazard Areas. As a result, and in light of the scale of future cumulative developments, the proposed Project’s incremental contribution to placing structures within Flood Hazard Areas would not be considerable. No mitigation measures to address cumulative impacts are required.

None of the infrastructure associated with the proposed Project would be situated within a watercourse. Although the proposed route does span multiple waterways, structures would be located on nearby hillsides and other land areas and would be engineered to withstand stresses resulting from their proximity to the waterways. Implementation of APM HYD-7 would reduce potential impacts resulting from the placement of transmission towers in a Flood Hazard Area to less than considerable level. No mitigation measures to address cumulative impacts are required.

Would the proposed Project,in combination with other cumulative projects, expose people or structures to a significant risk of loss, injury or death involving flooding, including flooding as a result of the failure of a levee or dam?

The proposed Project would not expose people or structures to a significant risk of loss, injury or death involving flooding because: a) the project would comply with all FEMA regulations on development in Flood Hazard Areas; b) no people or structures would be situated within a watercourse; c) construction activities do not have the potential to cause the failure of a levee or dam.; and d) Implementation of APM HYD-7 (Design and Site Structures to Avoid and Minimize Flood Damage) would reduce the proposed Project’s susceptibility to flood damage. The proposed Project’s incremental contribution of cumulative risks from flooding would be less than considerable. No mitigation measures to address cumulative impacts are required.

Would the proposed Project, in combination with other cumulative projects, result in or be subject to inundation by seiche, tsunami, or mudflow?

Because no large water bodies exist in the vicinity of the proposed Project, there would be no potential impact from tsunamis and seiches. Portions of the TRTP would be located in areas of steep unstable slopes that are potentially susceptible to mud flows and other erosion forces. Implementation of APM HYD-1 and APM HYD-7 and appropriate Geology and Soils APMs would minimize potential impacts such that the proposed Project’s incremental contribution would be less than cumulatively considerable. No mitigation measures to address cumulative impacts are required.

5.5.9 Land Use

The geographic scope for the cumulative impact analysis associated with land use encompasses the ANF and communities that would be traversed by the proposed Project. These include the following cities and unincorporated communities in Kern County, Los Angeles County, and San Bernardino County:

5.5.9.1 Cumulative Impact Analysis

Rapid development and population growth has been ongoing within incorporated areas (such as in the Cities of Lancaster, Palmdale, and Ontario) and the unincorporated area of Los Angeles and San Bernardino counties. Less development has been noted in the unincorporated areas of Kern County that would be traversed by or adjacent to the Project.

Past and ongoing development can result in a permanent change in land uses, and therefore have an impact on existing land uses. The siting of new projects and development is often located in existing open space areas, and has also extended across existing agricultural uses, especially in northern Los Angeles County (see Section 5.5.2 for a discussion of cumulative impacts to agricultural lands). Past development within Los Angeles, San Bernardino, and Kern counties has already altered existing land uses and permanently precluded some land uses such as open space and agriculture. Consequently, the impacts of projects listed in Table 5.3-2 that encroach and permanently alter existing land uses could be cumulatively considerable.

The potential for land use impacts of the proposed Project to combine with the effects of other projects within the geographic scope of the cumulative analysis are described below.

Would the proposed Project, in combination with other cumulative projects, physically divide an established community?

The proposed Project would take place primarily in existing and expanded T/L R‑O‑W and at substation locations, with temporary construction staging areas located on vacant land. The proposed Project is not expected to contribute to cumulative impacts resulting from dividing an established community. Segments 5, 6, 7, and most of 11 would be constructed within an existing T/L R‑O‑W, and since T/Ls already exist along these Segments, there would be no additional division of communities. Segments 4, 8, 10, and 11, as well as new and expanded substations included in Segment 9, would require acquisition of additional land and/or R‑O‑W. These segments would not divide established communities, as the additional R‑O‑W will be acquired adjacent to the existing T/L corridor and where the current land use is vacant, agricultural, or open space. A portion of acquired R‑O‑W along Segment 8 would traverse proposed Specific Plan areas. However, development of the Specific Plans would not be affected by the proposed Project, as the existing T/L corridor was considered in the design of these plans. No cumulative impacts are expected No mitigation measures to address cumulative impacts are required.

Would the proposed Project, in combination with other cumulative projects, conflict with any applicable land use plan, policy, or regulation of an agency with jurisdiction over the project, adopted for the purpose of avoiding or mitigating an environmental effect?

As proposed, the Project would not create impacts to planned developments within the Specific Plan areas identified in this PEA. No current or future projects have been proposed in the vicinity of the Project that would contribute to a cumulative impact to planned development within these communities. As such, no cumulative impacts to planned developments would be anticipated to occur. Construction and operation of the proposed Project would not require removal of any existing residential, commercial, or industrial structures. No impacts are anticipated. No mitigation measures to address cumulative impacts are required.

Though the proposed Project could potentially conflict with some land use plans, policies, and regulations, the impacts are less than significant due to the CPUC’s jurisdiction over electric power line projects and substations pursuant to General Order No. 131-D. As noted, the CPUC requires that public utilities consult with local agencies and consider local regulations in locating these projects. The relevant policies are related to protecting the environment and avoiding impacts. In this way, the proposed Project has been designed to minimize or avoid impacts where possible. As a result, the incremental contribution of the proposed Project with respect to conflicts with applicable plans, policies, or regulations would be less than cumulatively considerable. No mitigation measures to address cumulative impacts are required.

Would the proposed Project, in combination with other cumulative projects, conflict with any applicable habitat conservation plan or natural conservation plan?

The proposed Project is not expected to have significant effects due to conflicts with local Habitat Conservation Plans (HCPs) and Sensitive Environmental Areas (SEAs). Segments 4, 5, and 10, and the Whirlwind, Antelope, and Vincent substations (which are components of Segment 9) are entirely within the West Mojave Plan (WMP) (BLM, 2006). A portion of Segments 6 and 11 are also within the WMP. However, the WMP is currently applicable to federal lands only. Segments 4, 5, 6, 10, 11 and the Whirlwind, Antelope, and Vincent Substations would not be located on federal lands. Therefore, the proposed Project would not conflict with the WMP. No mitigation measures to address cumulative impacts are required.

A portion of the Western Riverside County Multiple Species HCP (MSHCP)is located within the 0.5-mile buffer from the Mira Loma Substation and Segment 8, but does not intersect Segment 8. No impacts are expected. No mitigation measures to address cumulative impacts are required.

Policies and guidance related to SEAs are part of the Los Angeles County General Plan, and therefore, a local land use plan. As the CPUC has preemptive jurisdiction over the construction, maintenance, and operation of public utilities in the State of California, no local plan consistency evaluations are required for the proposed Project or alternatives.

No cumulative impacts resulting from a conflict with an HCP, SEA, or HCCP are expected to occur. No mitigation measures are required. No mitigation measures to address cumulative impacts are required.

5.5.10 Mineral Resources

The proposed Project is not expected to have any adverse impacts to Mineral Resources and, therefore, would not incrementally contribute to cumulative impacts. No mitigation measures to address cumulative impacts are required.

5.5.11 Noise

5.5.11.2 Introduction

This section assesses the proposed TRTP with regard to whether a particular impact of the proposed Project could combine with similar effects of other projects to create cumulative noise impacts. The TRTP when considered together with other reasonably foreseeable projects from a noise perspective has the potential to result in short term noise impacts during the construction phase of the TRTP (i.e., between April 2009 and November 2003) in the Project area.

The proposed TRTP T/L routes traverse a wide variety of land uses, including open desert areas, mountainous open and forested areas, residential communities, commercial, and industrial areas. Past development and population growth within the various cities traversed by the TRTP segments and in adjacent unincorporated areas have expanded the potential for man-made noise, mainly due to roadway traffic, air traffic, and ongoing construction projects. Due to the multiple types of land uses that have developed, a wide range of noise sources occur in the geographic area and will continue to occur in the cumulative baseline.

Future baseline noise levels within the geographic area described above are expected to be incrementally higher than the levels in the present regional setting where increased urbanization, population growth, or human activity occurs. This is particularly true for the areas where large-scale residential development projects are currently under construction and for open areas that currently have relatively low ambient noise levels. Approved and pending projects (future), listed in Tables 5.3-1 and 5.3-2 and shown on Figure 5.3-1 [Sheet 1, 2] include multiple residential development projects. These projects would add to the future noise levels of the geographic area.

5.5.11.2 Cumulative Impact Analysis

Potential cumulative construction and operations phase noise impacts associated with the TRTP are addressed below. As discussed in Section 4.12.5 (Applicant Proposed Measures [APMs]) SCE has incorporated four APMs into the Project design to avoid or reduce potential Project-related noise effects.

Would the Project result in the exposure of persons to or generation of noise levels in excess of standards established in the local general plan or noise ordinance, or applicable standards of other agencies?

Construction noise impacts are usually sporadic and occur during daytime hours. For this reason, they rarely have a significant influence on 24-hour noise descriptions such as Community Noise Equivalent Level (CNEL) or a Day-night Average Noise Level (L_dn). Thus, measured by the standards used in most Noise Elements, TRTP construction noise would not be considered a significant impact. Construction noise is potentially significant, but short-term in nature and minimized by limiting the hours of construction, which is built into the proposed TRTP design. TRTP specific construction phase impacts would be expected to be less than significant. The proposed TRTP’s potential construction noise impacts would be short term, temporary, less than significant, and would not be expected to contribute considerably to any significant cumulative noise impacts in the Project area that would exceed applicable noise standards.

Operational phase corona discharge noise from 500 kV and 220 kV T/Ls as well as noise from substation transformers are normally below applicable standards at the edge of the T/L R‑O‑Ws and at substation boundaries; therefore, operational phase noise impacts would be expected to be less than significant. Operational phase TRTP noise impacts would not be expected to contribute considerably to any cumulative exceedance of applicable noise standards in the Project area.

Would the Project result in the exposure of persons to or generation of excessive groundbourne vibration or groundbourne noise levels?

Construction and operation of proposed TRTP facilities would not involve activities with the potential to generate excessive groundbourne vibration or noise levels. Potential cumulative impacts related to groundbourne vibration and/or noise would be less than significant.

Would the Project result in a substantial permanent increase in ambient noise levels in the project vicinity above levels without the Project?

Operation of proposed TRTP facilities (e.g., T/Ls and substations) would not result in substantial increases in noise levels in the Project vicinity due to T/L related corona noise (estimated at 40 to 50 dBA at the edge of the T/L R‑O‑Ws) or substation transformers (estimated at 50 to 60 dBA at 100 feet from the source). TRTP operational noise impacts would be expected to be less than significant and would not contribute considerably to any significant cumulative increase in ambient noise levels in the Project area.

Would the Project result in a substantial temporary or periodic increase in ambient noise levels in the project vicinity above levels existing without the Project?

The proposed TRTP would not result in substantial temporary or periodic increases in ambient noise levels in the Project vicinity with the possible exception of helicopter generated noise during construction and infrequent maintenance operations (e.g., once per year T/L inspection). Impacts would be short-term, transient, less than significant, and would not contribute considerably to significant cumulative increases in ambient noise levels existing without the Project.

For a Project located within an airport land use plan or, where such a plan has not been adopted, within two miles of a public airport or public use airport, would the Project expose people residing or working in the Project area to excessive noise levels?

The proposed TRTP would not expose people residing or working in the Project area to long-term excessive noise levels regardless of the location with respect to airports. Therefore, there would be no impact and no potential to contribute to cumulative impacts.

For a project within the vicinity of a private airstrip, would the project expose people residing or working in the project area to excessive noise levels?

The proposed TRTP would not expose people residing or working in the Project area to excessive noise levels regardless of the location with respect to private airstrips. Therefore, there would be no impact and no potential to contribute to cumulative impacts.

With implementation of APMs for TRTP noise (see Section 4.14.5), significant cumulative noise impacts would not be expected to occur, and no mitigation measures are necessary to reduce cumulative noise impacts.

5.5.12 Population and Housing

The following section analyzes the proposed Project with respect to whether a particular impact of the proposed Project would combine with similar effects of other projects to create cumulative population or housing impacts. The geographic extent for the analysis of includes Kern, Los Angeles, and San Bernardino counties.

5.5.12.1 Cumulative Impact Analysis

The three counties within the Project geographic extent are marked with substantial past and ongoing development and population growth, particularly in Los Angeles and San Bernardino counties. Section 4.13 Population and Housing provides existing population, housing, and employment conditions within the geographic scope area.

As shown in population forecasts in Table 5.4-1, the three-county region is projected to undergo rapid population growth. In this way, as the population increases through an indirect and direct influence of development, housing demands and workforce pools expand to serve the growing population and development needs. In addition, continued development creates more infrastructure and development affecting employment opportunities.

Projects listed in Table 5.3-2 support the rapid population growth projections, with the dominant majority of projects relating to residential development (large-scale planned communities, small-scale residential, and infill and redevelopment). These projects are located in both developed and undeveloped areas, which reflect the ongoing and continuing expansion and build-out. Cumulatively considerable impacts are those which would result in the potential impacts to residential structures from displacement issues and increased housing demand.

Would the proposed Project, in combination with other cumulative projects, induce substantial population growth in an area, either directly or indirectly?

Construction and operation of the proposed Project does not involve constructing or proposing new homes and businesses; therefore, the proposed Project would not directly contribute to population growth. No mitigation measures to address cumulative impacts are required.

The workforce required for the proposed Project construction would be drawn from regional and non-regional labor pools. Within the context of the construction workforce required for the cumulative projects, the labor force needed to construct the proposed Project would be a negligible fraction of the available labor pool. Furthermore, given that construction needs are temporary, few, if any, non-local construction workers are expected to permanently relocate to the area. Any contribution to growth would be less than considerable. No mitigation measures to address cumulative impacts are required.

As discussed in Section 7.0, Growth-Inducing Impacts, the proposed Project would not induce growth, but instead is being developed to accommodate both existing and forecast load demand. In addition, one of the purposes of the proposed Project is to interconnect and deliver energy from planned alternative energy projects (owned by independent power producers) to SCE’s load centers. While the proposed Project improves the overall system capability to adequately serve the existing and forecasted load demand, it is not intended to supply power related to potential growth for any one particular development. Those projects do not depend on the proposed Project to be built. Any contribution to growth would be less than cumulatively considerable. No mitigation measures to address cumulative impacts are required.

Would the proposed Project, in combination with other cumulative projects, displace substantial numbers of housing, necessitating the construction of replacement housing elsewhere?

Construction and operation of the proposed Project and would not require the removal of existing housing. Therefore, the proposed Project would have no cumulative contribution to impacts associated with the removal and replacement of housing. No mitigation measures to address cumulative impacts are required.

Would the proposed Project, in combination with other cumulative projects, displace substantial numbers of people, necessitating the construction of replacement housing elsewhere?

The proposed Project would not remove any housing or otherwise displace any people. It would not contribute to any cumulative impact associated with the need to construct new replacement housing. No mitigation measures to address cumulative impacts are required.

5.5.13 Public Services and Utilities

The geographic scope for the cumulative impact analysis associated with public services and utilities encompasses the ANF and communities that would be traversed by the proposed Project. These communities include the following cities and unincorporated areas in Kern County, Los Angeles County, and San Bernardino County:

5.5.13.1 Cumulative Impact Analysis

Public services are provided by county and municipal fire and police services to incorporated, unincorporated, and ANF jurisdictions. The utilities and service systems are supplied by both service providers and municipal entities to the cumulative impact area. Section 4.14 describes the existing public services and utilities systems within the geographic scope of this cumulative analysis.

Past development and ongoing population growth within the communities identified above place demands on capacities and capabilities of public services and utilities systems and, therefore, can affect existing public services and utilities systems. As the population increases through an indirect and direct influence of development, public services and utilities systems need to expand to serve the growing population. Cumulatively considerable impacts are those which would result in the potential significant impacts affecting capacities and capabilities of existing public services and utilities systems.

The cumulative impact analysis below discusses the potential for the utilities and service systems impacts of the proposed Project (see Section 4.14) to combine with the effects of past, present, and reasonable foreseeable future projects listed in Table 5.3-2.

Would the proposed Project, in combination with other cumulative projects, result in provision of new or physically altered governmental facilities for fire and police protection?

As a result of the temporary nature of the construction work, few, if any workers would be expected to permanently relocate to the Project area. As a result, the proposed Project would not increase demands on police protection and, hence, would have no impact that would require new or expanded police protection facilities. No mitigation measures are warranted.

Temporary construction activities could potentially increase fire risks, due to accidents or negligence by the construction personnel or equipment. As a result, SCE proposes to implement APM PUB-1, SCE Fire Plan (see Appendix D), which addresses fire prevention practices and emergency contingency procedures that would be implemented in the event of such an incident. Implementation of the Plan is expected to prevent potential fire incidents, and provide quick response and effective suppression of any fires that may occur. In this way, potential fire risks during construction of the proposed Project would be minimized and the incremental contribution to the cumulative demand for fire protection would be less than considerable. No mitigation measures to address cumulative impacts are required.

Because the USDA Forest Service provides fire suppression service exclusively for National Forest Service lands, only development projects on NFS lands would potentially contribute to a cumulative impact on USDA Forest Service fire fighting facilities. As a result of the fire management practices (Appendix D) described above, in addition to the ANF’s network of fire protection services and multiple response resources, as discussed in Section 4.14, potential fire risks during construction of the proposed Project within the ANF would result in a less than considerable contribution to the cumulative demand for fire protection. As a result, no mitigation measures are required.

Potential fire risks during Project operation would typically result from inadequate brush or foliage clearance in the R‑O‑W, or problems with the T/L support structures. SCE’s operation and maintenance procedures for the proposed T/Ls involve periodic inspection (e.g., at least once per year) via helicopter and truck where accessible, maintenance of the T/L corridors and access roads, and maintenance on the T/L on an as-needed basis. Such practices would also apply to Project areas within ANF lands. In this way, potential fire risks during Project operation would be minimized such that the incremental contribution to the cumulative demand for fire protection would be less than cumulatively considerable. No mitigation measures are required.

Operation of the proposed Project is expected to result in a negligible number of worker relocations to the Project area; consequently, the Project operation would not result in a cumulatively considerable impact to police protection services. No mitigation measures to address cumulative impacts are required.

Would the proposed Project, in combination with other cumulative projects, result in provision of new or physically altered governmental facilities for schools or parks?

As a result of the temporary and transient nature of the construction work, few, if any workers would be expected to permanently relocate to the Project area. Operation of the proposed Project would be conducted by SCE’s existing workforce and if additional personnel were needed, it is likely they would be drawn from the large regional workforce. Furthermore, the proposed Project would not contribute to regional population growth (see Section 7.0, Growth-Inducing Impacts). Because construction and operation of the proposed Project is expected to result in a negligible number of worker relocations to the Project area, the proposed Project’s incremental contribution to cumulative impacts on schools and parks would be not be considerable. No mitigation measures are required.

Would the proposed Project, in combination with other cumulative projects, result in provision of other new or physically altered governmental public facilities?

Numerous major hospitals along the Project route have capabilities and facilities to treat medical emergencies. The peak construction workforce is estimated to number approximately 350 workers over a large geographic area. Relative to the number of major medical facilities along and within the Project area, any medical emergencies that may arise during construction would not be expected to place an undue burden on local hospitals and new or expanded facilities would to be required. No impact is anticipated; therefore, no mitigation measures are needed.

As discussed above, operation of the proposed Project would result in a negligible, if any, relocation of new workers to the Project area, and the Project not result in a direct increase in the local population (Section 7.0, Growth-Inducing Impacts). As a result, the proposed Project would not increase any demands on other public facilities and hence, would result in no cumulatively considerable effects on other public facilities. No mitigation measures to address cumulative impacts are required.

Would the proposed Project, in combination with other cumulative projects, exceed wastewater treatment requirements of the applicable regional water quality control board?

Construction of the proposed Project does not involve wastewater treatment systems subject to Regional Water Quality Control Board water quality limits. Operation of the new, expanded, or upgraded substations may potentially generate stormwater runoff subject to Regional Water Quality Control Board water quality standards. As a result, SCE would prepare and implement Spill Prevention, Control and Countermeasure plans where applicable to prevent and manage potential introductions of hazardous materials into storm water discharges (see Section 4.8). Operation of the proposed Project therefore would not be expected to violate Regional Water Quality Control Board stormwater quality limits, and therefore the proposed Project would not result in a cumulatively considerable contribution that leads to an exceedance of applicable water quality standards. No mitigation measures to address cumulative impacts are required.

Would the proposed Project, in combination with other cumulative projects, require or result in the construction of new water or wastewater treatment facilities or expansion of existing facilities?

The proposed Project area is currently served by multiple water and wastewater treatment facilities (identified for each jurisdiction in Section 4.14) which currently provide large-scale service capabilities to the Project area. Water consumed during construction of the proposed Project consists of that used for fugitive dust mitigation and worker consumption, and would be considered a minimal quantity with respect to available supplies. Wastewater generated during construction of the proposed Project would be limited to quantities generated by the workforce, which at any one time is expected to average approximately 155 workers. It is expected that construction personnel would utilize portable toilets and would not cause direct discharges to sanitary sewer systems. The quantity of wastewater generated from these workers would be a negligible contribution to the existing and projected wastewater load. Therefore, construction of the proposed Project would not result in a considerable cumulative impact to water and wastewater treatment facilities. No mitigation measures to address cumulative impacts are required.

Operation of the proposed Project is expected to be conducted by SCE’s existing workforce, with few, if any, new employee additions. As a result, the proposed Project would not result in the need for new water or wastewater facilities. Any contribution would be less than considerable. No mitigation measures to address cumulative impacts are required.

Would the proposed Project, in combination with other cumulative projects, require or result in the construction of new storm water drainage facilities or expansion of existing facilities, the construction of which would cause significant environmental effects?

The proposed Project includes construction and expansion of storm water drainage facilities. SCE’s construction practices include preparation and implementation of a construction SWPPP that would avoid and minimize potential sources of storm water contamination and other environmental impacts to less than significant levels. Operation of the proposed Project also would not require additional provision for storm water drainage facilities. As a result, the proposed Project’s incremental contribution to cumulative impacts would not be considerable. No mitigation measures to address cumulative impacts are required.

Would the proposed Project, in combination with other cumulative projects, result in insufficient water supplies available to serve the project from existing entitlements and resources?

During construction of the proposed Project, water would be required for dust suppression and domestic uses for the workers. As discussed above, the quantity of water needed represents a small and temporary demand of relative to regional water availability. During operation, the proposed Project would require negligible amounts of water for maintenance activities and would not substantially change the demands placed on water suppliers. The proposed Project’s incremental contribution to cumulative impacts to water supplies would not be considerable. No mitigation measures to address cumulative impacts are required.

While ANF lands include watersheds necessary for the health and availability of water supply within the area, it is not anticipated that these lands would be affected by new or expanded water entitlements or resource facilities. Additionally, because the nature of projects on ANF lands are largely recreational or infrastructure related to maintaining or improving the natural conditions within the Forest, and are not utility intensive projects such as residential, commercial, or industrial projects, the past, ongoing, and future projects on ANF lands combined with the proposed Project would not substantially affect water supplies. Consequently, the proposed Project would result in no cumulatively considerable impacts on the ANF. No mitigation measures to address cumulative impacts are required.

Would the proposed Project, in combination with other cumulative projects, result in a determination by the wastewater treatment provider which serves or may serve the project that it has inadequate capacity to serve the project’s projected demand in addition to the provider’s existing commitment?

As previously mentioned, the proposed Project area is currently served by multiple wastewater treatment facilities (identified for each jurisdiction in Section 4.14) which currently provide large-scale service capabilities to the Project area. Wastewater generated during construction of the proposed Project would be limited to quantities generated by Project personnel and would be accommodated by portable restrooms brought to the staging areas. The portable toilets would be pumped into septic tanks or municipal sewage systems, as appropriate.

The Project construction would reach a peak workforce of 350 personnel. While a portion of these workers may originate from non-regional labor pools, the quantity of wastewater generated from these workers is expected to contribute negligible amounts to the existing wastewater load. Within a cumulative context, the additional wastewater generation represents minimal and temporary fractions. In this way, construction of the proposed Project would contribute no cumulatively considerable impacts to wastewater treatment facilities, capacities. No mitigation measures to address cumulative impacts are required.

Operation of the proposed Project is expected to be conducted by SCE’s existing workforce, with few, if any, new employee additions. As a result, the proposed Project would be expected to generate only minimal wastewater quantities, which would contribute no cumulatively considerable impacts to wastewater treatment facility capacities. No mitigation measures to address cumulative impacts are required.

Would the proposed Project, in combination with other cumulative projects, be served by a landfill with insufficient permitted capacity to accommodate the project’s solid waste disposal needs?

As described above in Section 4.14, solid waste generated during proposed Project construction would be within the capacities of local landfills for the proposed Project. Additionally, SCE’s recycling efforts would minimize the amount of solid waste disposal.

Project operations would generate minimal amounts of solid waste, which would generally consist of brush material cleared from the R‑O‑W. To the extent practical, SCE would allocate the solid waste to waste facilities incorporating waste diversion processes, which would minimize the potential impact on existing landfill capacities. In this way, the incremental contribution of the proposed Project to the solid waste stream would be less than cumulatively considerable. No mitigation measures to address cumulative impacts are required.

Would the proposed Project, in combination with other cumulative projects, violate federal, state, and local statutes and regulations related to solid waste?

SCE would recycle waste materials to the maximum extent practical, and expects to recycle at least 50 percent of the construction and demolition waste materials such as steel from LSTs. Solid waste generated during the proposed Project operation would be essentially limited to trash from the substations which would be diverted into local waste processes that would comply with solid waste requirements. Therefore, construction and operation of the proposed Project is not expected to violate applicable statutes and regulations relating to solid waste and hence, would not contribute to cumulative impacts. No mitigation measures to address cumulative impacts are required.

5.5.14 Recreation

The geographic area considered for the evaluation of cumulative effects on recreation is the linear extent of the overall proposed Project (Segments 4-11) and a width of 1 mile from the edge of the R‑O‑W or substation property (i.e., a study area 2 miles wide, centered on the project). Many of the projects considered in the cumulative projects list extend beyond this distance, but the effects of the proposed TRTP Project on recreational resources would be limited just to the T/L R‑O‑W and substation properties and their immediate vicinity.

5.5.14.1 Cumulative Impact Analysis

Would the proposed Project, in combination with other cumulative projects, increase the use of existing Neighborhood and regional parks of other recreational facilities such that substantial physical deterioration of the facility would occur or be accelerated?

Ongoing land development projects that provide new residences to accommodate population growth throughout the regions crossed by the proposed Project will affect recreational facilities. As populations increase, the demand for parks, sports fields, and other recreational areas and programs will also increase. As the population increases, there will be greater demand placed on open space areas, trails, and natural park areas. These effects would be greatest in those areas experiencing the most rapid population growth and increases in new land development. In general terms, these are areas where incorporated cities have considerable vacant land suitable for development. Palmdale and Lancaster are typical of such areas, but other cities and unincorporated areas along the various project segments continue to experience new development as well. In all of these areas, parkland is dedicated at the time subdivisions are approved (or in lieu fees are paid for this purpose). Local city and county governments are responsible for planning and developing parks and recreational facilities to serve their populations.

At the same time, regional recreational facilities are developed by higher levels of governments, including the Federal Government (U.S. Forest Service), State of California (Parks and Recreation Department and Department of Fish and Game), and county governments. These provide special and unique recreational opportunities for people over a very large area.

The increased demand for recreational facilities caused by the increase in population is met through regional and local government planning, with implementation using a variety of techniques. These include the exactions of parkland in the subdivision process mentioned above, and the use of general fund money, user fees, grants, and cooperative efforts among governments or with non-profit organizations.

The TRTP itself would neither increase nor decrease the demand for recreational facilities. Thus, it would have no project specific effect and it would not contribute towards cumulative demands for recreational facilities. The only effect of the Project on any recreational uses would be the temporary restriction of access to some recreational facilities during periods of construction. These effects would be very limited in terms of the areas affected and in terms of the length of time for the effect. Only those recreational facilities directly within existing R‑O‑Ws or immediately adjacent to them would be affected. As construction moved along any given project segment, the length of time that access might be restricted would vary from a few hours to a few days. In all cases, SCE would coordinate with the appropriate government agency/entity. Thus, the Project’s contribution towards cumulative demand for, or use of, recreational facilities would be less than considerable. No mitigation measures to address cumulative impacts are required.

Would the proposed Project, in combination with other cumulative projects, include recreational facilities or require the construction or expansion of recreational facilities which might have an adverse physical effect on the environment?

The proposed TRTP does not involve the construction of new recreational facilities. Cumulative growth and development in the region does include the construction of new recreational facilities. In most cases, new recreational facilities are neighborhood or community parks that are developed within subdivisions to serve new or existing neighborhoods. Larger regional recreational facilities, such as those along the San Gabriel River, are also planned and developed by local, county, state, and federal government agencies.

The only potential effects of the TRTP on recreational facilities may be the temporary and limited restriction of access to those facilities located directly within the R-O-W or immediately adjacent to it. In all cases where this would occur, alternate access is available using existing roadways and trails so no new recreational facilities or access would have to be constructed. The proposed Project would, therefore, have no effect in terms of constructing new recreational facilities that might involve physical changes. It would not contribute towards cumulative effects related to the construction of new recreational facilities. No mitigation measures to address cumulative impacts are required.

5.5.15 Transportation and Traffic

5.5.15.1 Cumulative Impact Analysis

Would the proposed Project, in combination with other cumulative projects, cause an increase in traffic which is substantial in relation to the existing traffic load and capacity of the street system?

Potential transportation and traffic-related cumulative impacts would be limited to the construction phase because routine Project operations involve only periodic (e.g., annual) maintenance visits. Impacts would thus be temporary and primarily involve a small increase in traffic on roadways and a small number of temporary lane closures or and/or road closures where T/L conductor stringing activities would cross roadways. A maximum of approximately 155 construction workers would be working along the TRTP at any one point in time. These workers would be traveling to and from construction staging areas in 7-8 person-capacity vehicles. Given the size of local populations, the temporary addition of a small number of construction workers to area roadways would not result in a considerable cumulative impact. No mitigation measures to address cumulative impacts are required.

Would the proposed Project, in combination with other cumulative projects, exceed a level of service (LOS) standard established by the county congestion management agency for designated roads or highways?

Construction of the proposed Project would be short-term, generally linear in nature, and would involve a relatively small construction workforce. Road closures would require intermittent traffic detours or controlled continuous traffic breaks which would temporarily disrupt traffic flow. Such closures and detours are routinely conducted by Caltrans, local agencies and public utilities in all urban areas, and lane or road closures necessary for construction would be conducted in accordance with SCE APMs designed to avoid and minimize Project impacts on local streets, highways and rail lines. These include: APM TRA-1 (minimize use of or work on local streets); APM TRA-2 (obtain encroachment permits or similar authorizations wherever local streets must be used for more than normal street operations); APM TRA-3 (use guard poles, netting and other means of protecting moving traffic and structures when stringing or other Project construction activities require crossing streets, highways or rail lines. If necessary on state highways, provide continuous traffic breaks operated by the California Highway Patrol [CHP]); and APM TRA-4 (prepare traffic control and other management plans). In addition, any Project construction related damage to local streets would be addressed by APM TRA-5 (repair any Project-related damage to local streets).

Implementation of these APMs would reduce potential incremental contributions to cumulative impacts on roadway LOS to less than considerable levels, particularly when compared to the scale of impacts that may occur from the construction of future foreseeable projects. No mitigation measures to address cumulative impacts are required.

Would the proposed Project, in combination with other cumulative projects, result in a change in air traffic patterns, including either an increase in traffic levels or a change in location that results in substantial safety risks?

Several TRTP segments are near small airfields and airports and some towers could exceed Federal Aviation Administration (FAA) height restrictions. SCE would be required to consult and coordinate with FAA in accordance Title 14 FAR 77 and SCE would be required to conform to all relevant FAA adopted safety standards and guidelines. This impact is not expected to combine with impacts of other projects and cumulative impacts are not expected. No mitigation measures to address cumulative impacts are required.

Would the proposed Project, in combination with other cumulative projects, substantially increase hazards due to a design feature or incompatible uses?

The proposed Project would not involve, create, or increase hazards at applicable transportation-related facilities in the Project area and would not involve activities or features that would create incompatibility with existing land uses such as farming operations. As a result, the proposed Project would not be expected to contribute to cumulative effects. No mitigation measures to address cumulative impacts are required.

Would the Project result in inadequate emergency access?

With implementation of APM TRA-1 through APM TRA-4, the proposed TRTP would not significantly affect emergency response along any of the roadways traversed by the proposed T/L route. For example, APM TRA-3 requires the use of guard poles, netting, or similar means at T/L roadway crossings to protect moving traffic, and APM TRA-4 requires use of traffic control and other traffic management techniques, where necessary, to minimize project impacts on traffic flow and access. As a result, the proposed Project’s contribution to cumulative impacts would be less than significant. No mitigation measures would be required.

Would the proposed Project, in combination with other cumulative projects, result in inadequate parking capacity?

Construction of the proposed TRTP would not create a significant demand for offsite parking facilities, as construction workers would park in designated areas such as marshalling yards and would not utilize offsite parking facilities. As a result, construction of the proposed Project would not contribute to cumulative effects. No mitigation measures to address cumulative impacts are required.

Operation of the proposed TRTP involves routine visual inspection of Project facilities at least one per year and occasional maintenance work as needed along the T/L, and periodic maintenance visits within minimal trip-making to the substation facilities. Parking would take place within the Project Area, and would not utilize offsite parking facilities. As a result, the proposed Project would not contribute to cumulative effects. >No mitigation measures to address cumulative impacts are required.

Would the proposed Project, in combination with other cumulative projects, conflict with adopted policies, plans, or programs supporting alternative transportation?

The proposed Project would not conflict with adopted policies supporting alternative transportation facilities or strategies. As a result, the proposed Project would not contribute to cumulative impacts. No mitigation measures to address cumulative impacts are required.

5.5.16 Paleontological Resources

5.5.16.1 Cumulative Impact Analysis

Would the proposed Project, in combination with other projects, directly or indirectly destroy a unique paleontological resource or site?

The cumulative projects could affect paleontological resources but the fossil-bearing strata that could be affected are wide-spread in the region, and most if not all projects would undergo CEQA review, and impacts to paleontological resources would likely be subject to avoidance and minimization measures similar to SCE’s APMs. As a result, no significant cumulative impacts to paleontological resources are anticipated. Even in combination with other past, current, and future projects in the area, the proposed Project would not have a cumulatively considerable impact on paleontological resources. No mitigation measures to address cumulative impacts are required.

TABLE 5.3-2
CUMULATIVE PROJECTS LIST¹

N/A = Not found in available data sources. Although not mapped, these projects are identified here to provide additional contextual information regarding cumulative developments in the region.

¹   Sources: see Section 5.2

² Refer to Figure 5.3-1 [Sheet 1, 2] for approximate locations of cumulative projects by Map ID number.