March 2011

BARREN RIDGE RENEWABLE TRANSMISSION PROJECT

Preliminary Geotechnical Evaluation

PROJECT NUMBER: 115244

PROJECT CONTACT: MIKE STRAND

EMAIL: [email protected]

PHONE: 714-507-2710

POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION

Preliminary Geotechnical Evaluation

PREPARED FOR: POWER ENGINEERS, INC. 731 E. BALL ROAD, SUITE 100 ANAHEIM, CA 92805

PREPARED BY: NINYO & MOORE 475 GODDARD, SUITE 200 IRVINE, CA 92618

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION

TABLE OF CONTENTS

1.0 INTRODUCTION ...... 1 1.1 STUDY PERSONNEL ...... 1 1.2 PROJECT DESCRIPTION ...... 1 1.2.1. Construction of New 230 kV Double-Circuit Transmission Line ...... 3 1.2.2. Addition of New 230 kV Circuit ...... 13 1.2.3. Reconductoring of Existing Transmission Line ...... 13 1.2.4. Construction of New Switching Station ...... 14 1.2.5. Expansion of Existing Switching Station ...... 15 1.2.6. Project-Wide Mitigation Measures ...... 15 1.2.7. Construction Work Force and Schedule ...... 15 2.0 REGULATORY FRAMEWORK ...... 17 3.0 PROJECT AREA OVERVIEW ...... 18 4.0 INVENTORY METHODS ...... 19 5.0 AFFECTED ENVIRONMENT ...... 20 5.1 REGIONAL GEOLOGIC SETTING ...... 20 5.2 STUDY AREA GEOLOGIC SETTING...... 20 5.3 SEISMICITY ...... 21 5.4 DATA INVENTORY RESULTS - SEGMENTS ...... 24 5.4.1. Geologic Resources ...... 24 5.4.2. Geologic and Seismic Hazards ...... 27 6.0 IMPACT ASSESSMENT - SEGMENTS ...... 37 6.1 METHODOLOGY ...... 37 6.2 GEOLOGIC RESOURCE SENSITIVITY ...... 37 6.3 POTENTIAL GEOLOGIC AND SEISMIC HAZARDS ...... 38 6.4 IMPACT LEVELS ...... 38 6.5 MITIGATION RECOMMENDATIONS ...... 39 6.5.1. Soil Loss/Soil Erosion ...... 39 6.5.2. Distinctive Geologic Features ...... 40 6.5.3. Surface Rupture ...... 40 6.5.4. Seismic Ground Shaking ...... 41 6.5.5. Liquefaction ...... 41 6.5.6. Landslides ...... 41 6.5.7. Subsidence ...... 42 6.5.8. Soil Settlement...... 42 6.5.9. Expansive Soils ...... 42 6.5.10. Corrosive Soils ...... 43 6.5.11. Groundwater ...... 43 6.5.12. Inundation from Dam Failure, Seiche or Tsunami ...... 43 7.0 IMPACT RESULTS ...... 45 7.1 NEW 230 KV TRANSMISSION LINE - SEGMENTS ...... 45 7.1.1. Soils ...... 49 7.1.2. Distinctive Geologic Features ...... 49 7.1.3. Surface Rupture ...... 51 7.1.4. Seismic Ground Shaking ...... 51 7.1.5. Liquefaction ...... 52

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7.1.6. Landslides ...... 53 7.1.7. Soil Erosion ...... 55 7.1.8. Subsidence ...... 56 7.1.9. Settlement ...... 56 7.1.10. Expansive Soils ...... 56 7.1.11. Corrosive Soils ...... 57 7.1.12. Groundwater ...... 58 7.1.13. Inundation from Dam Failure, Seiche or Tsunami ...... 59 7.2 NEW 230 KV CIRCUIT ...... 60 7.3 RECONDUCTORING ...... 60 7.4 NEW HASKELL CANYON SWITCHING STATION ...... 61 7.5 EXPANSION OF BARREN RIDGE SWITCHING STATION ...... 62 8.0 ALTERNATIVES...... 64 8.1 DEVELOPMENT OF ALTERNATIVES ...... 64 8.2 ALTERNATIVES DESCRIPTION ...... 64 8.2.1. Action Alternatives ...... 64 8.2.2. Summary Description of Action Alternatives ...... 73 8.2.3. No Action Alternative ...... 74 8.3 IMPACT ASSESSMENT—ROUTING ALTERNATIVES ...... 74 8.4 IMPACT RESULTS—ROUTING ALTERNATIVES ...... 74 8.5 NO ACTION ALTERNATIVE ...... 79 8.6 CUMULATIVE IMPACTS ...... 79 8.6.1. Introduction ...... 79 8.6.2. Impacting Factors ...... 79 8.6.3. Impact Area ...... 80 8.6.4. Cumulative Projects List – Major Present and Reasonably Foreseeable Future Actions ...... 80 8.6.5. Cumulative Impacts Summary ...... 88 9.0 REFERENCES ...... 90 10.0 ACRONYMS AND ABBREVIATIONS ...... 95

TABLES

TABLE 1-1. ANTICIPATED CONSTRUCTION SEQUENCE ...... 16 TABLE 1-2. CONSTRUCTION WORKFORCE AND SCHEDULE ...... 16 TABLE 1 – PRINCIPAL GEOLOGIC UNITS IN THE PROJECT STUDY AREA ...... 21 TABLE 2 – PRINCIPAL REGIONAL ACTIVE AND POTENTIALLY ACTIVE FAULTS ...... 22 TABLE 3 – SUMMARY OF U.S. DEPARTMENT OF AGRICULTURE U.S. GENERAL SOIL TYPES1 ...... 25 TABLE 4 – SUMMARY OF DISTINCTIVE GEOLOGIC FEATURES ...... 27 TABLE 5 – SUMMARY OF EARTHQUAKE FAULT ZONES ...... 28 TABLE 6 – SUMMARY OF GROUND SHAKING POTENTIAL ...... 29 TABLE 7 – SUMMARY OF LIQUEFACTION HAZARD ZONES ...... 30 TABLE 8 – SUMMARY OF MAPPED LANDSLIDES AND EARTHQUAKE-INDUCED LANDSLIDE HAZARD ZONES ...... 31 TABLE 9 – SUMMARY OF EROSION POTENTIAL AREAS TRAVERSED BY EACH SEGMENT1 ...... 32 TABLE 10 – SUMMARY OF EXPANSIVE SOIL POTENTIAL AREAS TRAVERSED BY EACH SEGMENT1 ... 33 TABLE 11 – SUMMARY OF CORROSIVE SOIL POTENTIAL AREAS TRAVERSED BY EACH SEGMENT1 ... 34 TABLE 12 – SUMMARY OF GROUNDWATER LEVELS BY SEGMENT1 ...... 35 TABLE 13 – SUMMARY OF DAM FAILURE INUNDATION AREAS ...... 36 TABLE 14 – SENSITIVITY RATINGS FOR GEOLOGIC RESOURCES ...... 38

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TABLE 15 – IMPACT LEVELS ...... 39 TABLE 16 – RELATIVE GEOLOGIC IMPACTS ...... 47 TABLE 17 – SUMMARY OF POTENTIAL INITIAL IMPACTS TO SOILS1 ...... 49 TABLE 18 – SUMMARY OF POTENTIAL INITIAL IMPACTS TO DISTINCTIVE GEOLOGIC FEATURES1 ..... 50 TABLE 19 – SUMMARY OF POTENTIAL INITIAL IMPACTS DUE TO EARTHQUAKE FAULT ZONES ...... 51 TABLE 20 – SUMMARY OF POTENTIAL INITIAL IMPACTS DUE TO GROUND SHAKING ...... 52 TABLE 21 – SUMMARY OF POTENTIAL INITIAL IMPACTS DUE TO LIQUEFACTION HAZARD ZONES .... 53 TABLE 22 – SUMMARY OF POTENTIAL INITIAL IMPACTS DUE TO MAPPED LANDSLIDES ...... 54 TABLE 23 – SUMMARY OF POTENTIAL INITIAL IMPACTS DUE TO EARTHQUAKE-INDUCED LANDSLIDE HAZARD ZONES ...... 55 TABLE 24 – SUMMARY OF POTENTIAL INITIAL IMPACTS DUE TO SOIL EROSION1 ...... 56 TABLE 25 – SUMMARY OF POTENTIAL INITIAL IMPACTS DUE TO CORROSIVE SOILS1 ...... 58 TABLE 26 – SUMMARY OF POTENTIAL INITIAL IMPACTS DUE TO GROUNDWATER1 ...... 59 TABLE 27 – SUMMARY OF POTENTIAL INITIAL IMPACTS DUE TO DAM FAILURE INUNDATION ...... 60 TABLE 28 – SUMMARY OF AFFECTED ENVIRONMENT FOR PROPOSED ALTERNATIVES ...... 73 TABLE 29 – SUMMARY OF THE PROPOSED ALTERNATIVE POTENTIAL INITIAL IMPACTS TO SOILS1 ... 74 TABLE 30 – SUMMARY OF THE PROPOSED ALTERNATIVE POTENTIAL INITIAL IMPACTS TO DISTINCTIVE GEOLOGIC FEATURES1 ...... 75 TABLE 31 – SUMMARY OF THE PROPOSED ALTERNATIVE POTENTIAL INITIAL IMPACTS DUE TO EARTHQUAKE FAULT ZONES ...... 75 TABLE 32 – SUMMARY OF THE PROPOSED ALTERNATIVE POTENTIAL INITIAL IMPACTS DUE TO GROUND SHAKING ...... 75 TABLE 33 – SUMMARY OF THE PROPOSED ALTERNATIVE POTENTIAL INITIAL IMPACTS DUE TO LIQUEFACTION HAZARD ZONES ...... 76 TABLE 34 – SUMMARY OF THE PROPOSED ALTERNATIVE POTENTIAL INITIAL IMPACTS DUE TO MAPPED LANDSLIDES ...... 76 TABLE 35 – SUMMARY OF THE PROPOSED ALTERNATIVE POTENTIAL INITIAL IMPACTS DUE TO EARTHQUAKE-INDUCED LANDSLIDE HAZARD ZONES ...... 77 TABLE 36 – SUMMARY OF THE PROPOSED ALTERNATIVE POTENTIAL INITIAL IMPACTS DUE TO SOIL EROSION1 ...... 77 TABLE 37 – SUMMARY OF THE PROPOSED ALTERNATIVE POTENTIAL INITIAL IMPACTS DUE TO CORROSIVE SOILS1 ...... 78 TABLE 38 – SUMMARY OF THE PROPOSED ALTERNATIVE POTENTIAL INITIAL IMPACTS DUE TO GROUNDWATER1 ...... 78 TABLE 39 – SUMMARY OF THE PROPOSED ALTERNATIVE POTENTIAL INITIAL IMPACTS DUE TO DAM FAILURE INUNDATION ...... 79 TABLE 8A. PROPOSED GENERATION PROJECTS IN THE PROJECT VICINITY...... 84 TABLE 8B. BLM RIDGECREST OFFICE APPLICATIONS FOR WIND AND SOLAR ENERGY GENERATION PROJECTS IN THE PROJECT VICINITY...... 85 TABLE 8C. PROPOSED LOCAL PROJECTS IN THE PROJECT VICINITY...... 88

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FIGURES

FIGURE 1-1. LADWP’S PROPOSED ACTION COMPONENTS...... 2 FIGURE 1-2. TYPES OF TOWERS ...... 3 FIGURE 1-3. FOUR-CIRCUIT TOWERS TO BE UTILIZED ...... 5 FIGURE 1-4. TYPICAL TOWER COMPONENTS ...... 6 FIGURE 1-5. PRELIMINARY ROUTING SEGMENTS ...... 8 FIGURE 1-6. THREE-CIRCUIT TOWER TYPES ...... 10 FIGURE 1-7. THREE-CIRCUIT TOWER MITIGATION ...... 11 FIGURE 8-1. ACTION ALTERNATIVES ...... 65 FIGURE 8-2. IDENTIFIED HELICOPTER MITIGATION LOCATIONS ...... 67 FIGURE 8-3. AVENUE L RE-ROUTE ON ALTERNATIVE 3 ...... 71 FIGURE 8-4. CUMULATIVE PROJECTS ...... 81

APPENDICES GEOTECHNICAL FIGURES FIGURE 1 – PROJECT AREA LOCATION MAP FIGURE 2 – GEOLOGIC MAP FIGURE 3 – FAULT LOCATION MAP FIGURE 4 – REGIONAL SOILS MAP FIGURE 4A – REGIONAL SOILS MAP LEGEND FIGURE 5 – EARTHQUAKE FAULT ZONES MAP FIGURE 6 – ESTIMATED PEAK HORIZONTAL GROUND ACCELERATION CONTOURS FIGURE 7 – LIQUEFACTION HAZARD ZONES MAP FIGURE 8 – MAPPED LANDSLIDE INVENTORY FIGURE 9 – EARTHQUAKE-INDUCED LANDSLIDE HAZARD ZONES MAP FIGURE 10 – SOIL EROSION POTENTIAL MAP FIGURE 11 – BRRTP PROPOSED PROJECT ALTERNATIVES

APPENDIX A – IMPACT ASSESSMENT TABLES APPENDIX B – USDA SOIL TABLE APPENDIX C – DETAILED CONSTRUCTION, OPERATION, AND MAINTENANCE PROCESS

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1.0 INTRODUCTION

The City of Los Angeles Department of Water and Power (LADWP) is proposing the Barren Ridge Renewable Transmission Project (BRRTP or Project) to access clean, renewable resources in the Tehachapi Mountains and Mojave Desert areas, and to improve reliability and upgrade transmission capacity.

LADWP, the US Department of Agriculture, Forest Service (USFS or Forest Service) and the U.S Department of the Interior, Bureau of Land Management (BLM) are preparing a joint Environmental Impact Statement (EIS) / Environmental Impact Report (EIR) for the proposed BRRTP. LADWP is the California Environmental Quality Act (CEQA) Lead Agency, while the USFS and BLM are the federal Co-Lead Agencies under the National Environmental Policy Act (NEPA). An EIS/EIR is an informational disclosure document used to inform agency decision makers and the public of the potential significant environmental effects of a project, identify possible ways to eliminate or minimize the potential significant effects, and describe reasonable alternatives to the Proposed Action /Project.

The purpose of the preliminary geotechnical evaluation is to assess the alternative corridors (segments) and proposed switching station within the Project study area in regards to potential geologic and seismic hazards and potential geologic impacts associated with implementation of the Project. The preliminary geotechnical evaluation: 1) presents regulatory framework, 2) provides an overview of the technical methodology used in collecting baseline conditions and evaluating impacts, 3) examines the affected environment within the study corridors and vicinity, 4) describes the impacts with respect to potential geologic and seismic hazards and potential geologic impacts from construction and operation of the Project, 5) evaluates the level of potential impacts based upon NEPA/CEQA significance criteria, and 6) presents specific recommendations for mitigation to reduce or eliminate potential impacts.

1.1 STUDY PERSONNEL Ninyo & Moore personnel who compiled background data, conducted geotechnical analysis, and prepared the preliminary geotechnical evaluation included Michael Rogers, an Engineering Geologist with over 20 years of professional experience; Carol Price, an Engineering Geologist with over 25 years of professional experience; and Jalal Vakili, Ph.D., a Geotechnical Engineer with over 40 years of professional experience. Mr. Rogers and Ms. Price hold licenses with the State of California as Professional Geologists and Certified Engineering Geologists, and Dr. Vakili holds a license with the state as a Registered Civil Engineer. Jesse Lahman provided GIS support for the Project.

1.2 PROJECT DESCRIPTION The BRRTP would be located in Kern and Los Angeles counties. As proposed by LADWP, it would be approximately 76 miles in length extending from the Barren Ridge Switching Station to Rinaldi Substation, and extending approximately 12 miles from the Castaic Power Plant to the proposed Haskell Canyon Switching Station. As shown in Figure 1-1, the proposed BRRTP would include the following: 1) Construction of approximately 61 miles of a new 230 kilovolt (kV) double-circuit transmission line from the LADWP Barren Ridge Switching Station to Haskell Canyon; 2) Addition of approximately 12 miles of a new 230 kV circuit on the existing double-circuit structures from Haskell Canyon to the Castaic Power Plant; 3) Reconductoring of approximately 76 miles of the existing Barren Ridge-Rinaldi (BR-RIN) 230 kV transmission line with larger capacity conductors between the Barren Ridge Switching Station and the Rinaldi Substation; 4) Construction of a new switching station in Haskell Canyon; 5) Expansion of the existing Barren Ridge Switching Station.

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FIGURE 1-1. LADWP’S PROPOSED ACTION COMPONENTS

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 2 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION 1.2.1. Construction of New 230 kV Double-Circuit Transmission Line The proposed double-circuit 230 kV transmission line component of the BRRTP would consist of two alternating current (AC) circuits from the Barren Ridge Switching Station to the proposed Haskell Canyon Switching Station in Haskell Canyon.

The proposed structures for the new transmission line would primarily be self-supporting double-circuit steel lattice towers fabricated from galvanized steel members, as shown on the left side of Figure 1-2. Depending on the environmental conditions of the surrounding terrain, the height of the proposed lattice structures would range from 110 to 195 feet, with an average tower-to-tower span of 1,000 to 1,100 feet. Appendix C lists the structure specifications for the number of structures per mile, average span length, and average heights for towers and components. Exact structure placement would be determined during engineering surveys and detailed design studies for the selected Alternative route following the Record of Decision (ROD) on the EIS/EIR. A variety of engineering, constructability, existing access, and environmental issues would be considered during detailed structure siting within the permitted ROW.

―Dead-end‖ towers of self-supporting, steel-lattice design would be required periodically to add longitudinal strength along the line. Dead-end towers would also be used at turn (angle) locations along the line, at heavily loaded tower locations, and at specific utility crossings (e.g., other transmission lines) for added safety. Dead-ended towers are of the same basic configuration as suspension towers (non-angle structures), the difference being in the tower ―arms,‖ insulator systems, and tower weights.

FIGURE 1-2. TYPES OF TOWERS

Self-supporting, tubular steel poles (TSP) have been proposed by LADWP as an available mitigation structure where appropriate to reduce potential impacts, such as conflicts with cultivation on agricultural lands. The TSPs can reduce impacts in some cases due to a smaller footprint than the proposed self- supporting steel lattice structures; however, more TSPs per mile are necessary due to a shorter average span between structures. The TSPs would have an average height range between 95 and 180 feet, depending on the conditions of the surrounding terrain, with an average tower-to-tower span of 700 to 800 feet. Refer to Figure 1-2 for an illustration of the double-circuit poles.

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For the majority of the alignment, the two new 230 kV circuits would be placed on new double-circuit transmission towers, but for approximately 1.5 miles, the circuits would be placed on existing four-circuit structures that are located just north of the proposed Haskell Canyon Switching Station. Between where the existing BR-RIN crosses Dry Canyon to the intersection of the Castaic transmission lines, LADWP has existing four-circuit towers with three vacant positions. The existing towers would be utilized in this section for the proposed 230 kV double circuit transmission line instead of constructing new towers. See Figure 1-3 for the location and illustration of the existing four-circuit towers to be utilized.

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FIGURE 1-3. FOUR-CIRCUIT TOWERS TO BE UTILIZED

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 5 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION The self-supporting steel lattice structures and TSPs would utilize concrete foundations. Steel lattice structures would require four footings (one for each leg); TSPs would require single footings. Footings would be steel-reinforced concrete pier type and be cast in place. The typical design for the concrete footings for lattice structures would be between 2.5 and 5.0 feet in diameter, with an average depth of 20 feet depending on soil conditions. Typical design for single foundations for TSPs would include augured holes approximately five to seven feet in diameter and 15 to 30 feet deep, depending on conditions. Formwork steel reinforcing would be assembled in the hole prior to casting concrete in place. Reinforcing steel would become integral to the lower leg of the steel lattice structure during assembly. An above- ground concrete form placed over each hole would result in a final concrete foundation height of 0.5 to 2.0 feet above ground level.

As illustrated in Figure 1-4, Typical Tower Components, each tower carries conductors (―wires‖), insulators, and ground wires. The conductor being considered for the new double-circuit 230 kV transmission line and installation of the Castaic – Haskell Canyon #4 circuit on existing structures is a bundled 715.5 kcmil ―Starling‖ ACSS/AW. The reconductoring of the BR-RIN transmission line between Barren Ridge Switching Station and Rinaldi Substation would require a bundled 1,433.6 kcmil ―Merrimack‖ ACSS/TW/HS conductor.

FIGURE 1-4. TYPICAL TOWER COMPONENTS

Each circuit would consist of three phases (―wires‖) as illustrated in Figure 1-4. To increase the current- carrying capability of the transmission lines and reduce power loss, the Proposed Action (Alternative 2) would utilize bundled conductors installed for each phase. The bundled conductors would consist of two conductor cables connected by a spacer. The new 230 kV double-circuit transmission line would consist of a total of six double-bundled (12 individual) wires.

Minimum conductor height above the ground, under normal operation of the line, is 30 feet. Greater clearances may be required in certain areas to allow for clearances over trees or other vegetation that

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 6 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION could pose a risk to the operation of the transmission line. Minimum conductor clearance would dictate the exact height of each tower based on topography and safety clearance requirements.

Insulators are used to provide the physical connection of conductors to structures. These system components are made of very low conducting materials (polymer insulators) that inhibit the flow of electric current from energized conductors to ground or to other energized system elements. Insulators and their associated hardware are to be configured in an ―I‖ assembly to support conductors while maintaining required distances between phases and grounded structures. Each ―I‖ string would consist of six-inch diameter insulators between six and eight feet long.

To shield conductors from hazard of direct lightning strikes by transferring lightning currents into the ground, overhead ground wires (shield wires) or fiber optic ground wire would be installed on top of new structures.

Construction of a transmission line involves the following general sequence of events: surveying activities; identifying and constructing access roads; clearing ROW and tower sites (including construction yards and batch plants); installing foundations; assembling and installing the towers; clearing, pulling, tensioning, and splicing; installing ground wires and conductors; installing counterpoise; switching station tie-in; and site upkeep and site reclamation. Various phases of construction would occur at different locations throughout the construction process for the BRRTP. This would require several contractors operating at the same time and in different locations. Refer to Appendix C for a description of each construction activity.

Existing paved and unpaved highways and roads would be used where possible. Roads along existing utility corridors would also be used where possible to minimize new access road construction. In locations where existing roads could be used, that are located in close proximity to the proposed or existing ROW centerlines, only new spur roads to the tower sites would be constructed. The specific locations and design of all new access and spur roads would be determined during final Project design.

It is anticipated that one or two construction yards or staging areas would be required for materials storage, construction equipment, construction vehicles, and temporary construction offices. Staging areas would be approximately five acres in size, and located centrally or near each end of the transmission line route. The staging areas would likely be located on previously disturbed land and would be level and surfaced with crushed aggregate base. The LADWP would negotiate with landowners for specific locations of the staging areas.

Routing In 2007, a siting analysis was conducted to identify appropriate sites for a new 230 kV transmission line. Over 200 miles of routing opportunities were identified and referred to as Segments A through I (see Figure 1-5). These segments were then combined to create end-to-end routing ―alternatives‖ as discussed in Section 8.2. All routing Segments were identified assuming the need for a 200-foot ROW for the new 230 kV transmission line and the use of conventional transmission line construction. However, as discussed in Section 8.2, the end-to-end alternatives have included specific mitigation measures to reduce certain impacts. These mitigation measures would eliminate the need for new ROW in some locations and would require the use of helicopters for tower assembly in designated areas on the ANF. Also, to the maximum extent possible, all existing access and spur roads would be utilized for the construction, operation, and maintenance of the BRRTP. Below is a brief description of each segment.

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FIGURE 1-5. PRELIMINARY ROUTING SEGMENTS

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 8 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION Segment A is 13 miles long and runs from LADWP’s Barren Ridge Switching Station to the unincorporated community of Mojave, California. It would traverse four miles of BLM managed public lands and parallel LADWP’s existing 230 kV Barren Ridge – Rinaldi Transmission Line (BR-RIN) and the 500 kV Pacific Direct Current Intertie (PDCI). It traverses four miles of BLM-managed lands.

Segment B is 27 miles long and starts just north of the unincorporated community of Mojave, California and travels south to a point one mile east of the Antelope Valley California Poppy Reserve. This segment parallels LADWP’s existing 230 kV BR-RIN and 500 kV PDCI transmission lines for its entire length.

Segment C is 22 miles long and begins at the location as Segment B, north of the unincorporated community of Mojave, California. Segment C parallels the Los Angeles Aqueduct in a southwest direction to Cottonwood Creek. No existing transmission lines are located within the aqueduct corridor; however, Southern California Edison’s (SCE’s) Tehachapi Renewable Transmission Project’s (TRTP) Alternative 10A is also proposed along the same corridor.

Segment D is 48 miles long and would traverse 16 miles of National Forest System (NFS) lands. This segment generally parallels the Los Angeles Aqueduct in a southwest direction, beginning near Cottonwood Creek and traveling to Lancaster Road. It then travels west to the Interstate 5 freeway utility corridor and continues southeast along LADWP’s existing Castaic – Rinaldi corridor to the proposed Haskell Canyon Switching Station. Five high voltage transmission lines are located along the Interstate 5 section of the segment. Oil and gas pipelines are also located in the same I-5 corridor. Continuing further south near Castaic Power Plant, Segment D would be located to the south of two existing LADWP double-circuit 230 kV transmission line towers until reaching the proposed Haskell Canyon Switching Station.

Segment E is 11 miles long and begins near Cottonwood Creek at the intersection of Segments C and D. Segment E travels in a southeast direction and intersects Segment B one mile east of the Antelope Valley California Poppy Reserve. Three existing high voltage transmission lines (Midway-Vincent 500 kV, Antelope-Vincent 230 kV, and Antelope-Mesa 230 kV) are located within the corridor that Segment E would parallel. SCE’s proposed TRTP Segment 4 is also proposed adjacent this same corridor.

Segment F is the shortest segment, at four miles in length, and begins at the intersection of Segments B and E one mile east of the Antelope Valley California Poppy Reserve. Three existing high voltage transmission lines (Midway-Vincent 500 kV, Antelope-Vincent 230 kV, and Antelope-Mesa 230 kV) are also located parallel to this segment.

The 115th Street Segment was proposed as a modification to avoid impacts to residents in the Antelope Valley near Segments F and H, described below. It begins mid-way within Segment F near SCE’s Antelope Substation and parallels 115th Street south to the California Aqueduct. No existing transmission lines occur within this corridor; however, TRTP’s proposed Segment 4 would be located along this alignment. This segment would split Segments F and H as shown in Figure 1-5 creating these Segments into F1, F2, H1 and H2.

Segment G is 21 miles long. Thirteen miles traverse National Forest System (NFS) lands. It travels south from the intersection of Segments B and F one mile east of the Antelope Valley California Poppy Reserve to the proposed Haskell Canyon Switching Station, located near the southern boundary of the ANF. It is a designated utility corridor containing LADWP’s existing 230 kV BR-RIN and 500 kV PDCI lines. The BRRTP proposes to use its existing four-circuit structures for two miles, from towers 234-3 to 236-2 (see Figure 1-3).

Segment 2a is seven miles long. It would bypass the unincorporated community of Green Valley and follow an existing fire road through ANF. Segment 2a would not parallel existing transmission facilities, and a new utility corridor would be required.

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 9 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION Segment H is 20 miles long and would parallel SCE’s Antelope-Pardee line. It starts near SCE’s Antelope Substation at the intersection of Segments F and I and traverses 13 miles of NFS lands to the proposed Haskell Canyon Switching Station. As requested by the USFS, all portions of this segment that fall within the northern and southern borders of the ANF would be constructed entirely by the use of helicopters. The helicopter construction requirement was established by the USFS for consistency of transmission line construction within the existing Antelope-Pardee transmission line corridor. No new access roads would be constructed except those required for pulling and tensioning sites or staging locations for construction materials. The addition of the 115th Street Segment, described above, splits the Segment into H1 (northern portion) and H2 (southern portion).

Segment I is 32 miles long. It begins near the Antelope Substation at the intersection of Segments F and H, and heads southeast through the City of Palmdale, parallel SCE’s existing high voltage transmission lines (Midway-Vincent 500 kV, Antelope-Vincent 230 kV, and Antelope-Mesa 230 kV). The segment continues directly south to an existing LADWP transmission line corridor, then continues in a southeast direction to the proposed Haskell Canyon Switching Station, parallel LADWP’s existing high voltage transmission lines (Victorville-Rinaldi 500 kV and Adelanto-Rinaldi 230 kV). A majority of this segment would be located outside of NFS lands. Two miles would be located on NFS lands.

Segment J is located parallel to the southern portion of Segment D. Segment J would consist of a new single 230 kV circuit to be placed on existing double-circuit towers between Castaic Power Plant and the proposed Haskell Canyon Switching Station (see discussion in Section 1.2.2 below).

Three-Circuit Tower Mitigation In areas where there are ROW expansion constraints and where LADWP has existing 230 kV transmission lines, LADWP is proposing to construct three-circuit towers within the existing ROW to carry the existing BR-RIN circuit and the two proposed Barren Ridge to Haskell Canyon (BR-HC) circuits. This would avoid various impacts, including the acquisition of residential property in the unincorporated communities of Willow Springs (milepost 27.1 to 27.6) and Elizabeth Lake and Green Valley (milepost 44.6 to 51.7). Refer to Figure 1-6 for an illustration of three-circuit tower types, and to Figure 1-7, the Three-Circuit Tower Mitigation Map, for proposed locations.

FIGURE 1-6. THREE-CIRCUIT TOWER TYPES

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FIGURE 1-7. THREE-CIRCUIT TOWER MITIGATION

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LADWP must maintain the electrical service along the existing BR-RIN transmission line to avoid impacts to the hydroelectric power plants north of the Barren Ridge Switching Station. Therefore, a temporary transmission line would be constructed to keep the BR-RIN circuit energized during construction of the three-circuit towers. After the temporary line is constructed, the existing BR-RIN single-circuit towers would be removed to allow the new three-circuit towers to be constructed within the existing ROW. Once construction of the three-circuit towers is completed, the temporary transmission line would be removed. The temporary transmission line is expected to be in place from six to nine months.

The temporary transmission line would be 7.5 miles long and would consist of wood and steel single poles with an average height of 95 feet, a 3-foot by 3-foot footprint, and an average of eight poles per mile. Construction would occur within a new temporary 80- to 100-foot ROW. The majority of the temporary transmission line would be constructed along San Francisquito Road. Portions would also be constructed along Elizabeth Lake Road and Johnson Road. Pole placement would be adjacent to public roadways wherever possible. If necessary, temporary ROW on private property would be needed where poles could not be placed within public road ROW. The majority of poles would be direct-embedded when set in place and would not require a permanent foundation. Where additional strength is necessary at larger angle points, steel poles would be required, which could require an excavation approximately 6 feet in diameter by 20 feet deep to accommodate the concrete pier foundation that would be cast in place. Once all the poles have been constructed and the conductor installed, the existing BR-RIN circuit would be connected into the temporary line and energized. The construction would require establishment of a staging area, work areas around poles, and pull and tension sites. Access to pole sites and pull and tension sites would be from the adjacent roadways.

Approximately seven miles of the existing BR-RIN single-circuit towers would be removed, with existing ROW utilized to access the existing towers. The new three-circuit towers would be placed within the existing ROW, utilizing existing access roads. Helicopter Mitigation, as described in this section below, would be applied in steeper terrain if additional access is required. The new three-circuit tower would require a 25-foot by 30-foot structure footprint and an average of seven structures per mile; the average structure height would be 170 feet, with a maximum tower-to-tower span length of 780 feet. The construction process for the new three-circuit towers would be the same as the double-circuit towers discussed above. After completion of construction of the three-circuit towers, the temporary transmission line would be removed and all temporary staging and work area land disturbances would be restored as close to previous conditions as possible and revegetated as required.

Helicopter Mitigation Within the ANF where the terrain is steep and access is limited, the USFS would require that the new double-circuit 230 kV structures be constructed with the use of helicopters (such as the Hughes 500 or Bell 212, or Sikorsky Skycrane). Although no specific locations for this mitigation have been identified for the Proposed Action, as defined, it is expected USFS would require the helicopter mitigation for construction in any area more than 300 feet from an existing road and with slopes greater than approximately 25 percent. The use of helicopters for the construction of transmission tower structures would eliminate the need for new access roads to structure locations, and would therefore minimize land disturbance associated with crane pads, structure laydown areas, and the trucks and tractors used for delivery of structures to sites. However, the following site and ground disturbing construction activities would be required to construct the new transmission line within the identified helicopter construction areas: portable landing pads, helicopter fly yards/staging areas and associated access roads, tower structure vegetation clearing, guard structures at major crossings, and access road pullouts.

Temporary 24-foot wide access roads would be required to access the helicopter fly yards/staging areas. The transmission line materials (tower steel, conductor reels, structure hardware, etc.) would be delivered by truck to the helicopter fly yards/staging areas. Vegetation clearing may be required at these sites to

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 12 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION ensure safe working conditions. The fly yards/staging areas would serve as helicopter support yards for fueling and maintenance, as well as for the transport of materials and personnel. Towers may also be assembled in sections at these yards prior to delivery to the tower sites. Heavy lift helicopters would then fly the towers from the yards to the tower sites.

Portable landing pads would be located at each tower site. These pads would allow helicopters to load and unload personnel, tools, and equipment necessary for construction of foundations and assembly of tower structures. Helicopter-constructed towers that would not be in close proximity to existing access roads would utilize micropile foundations. For each tower leg, micropile foundations would use a group of three to eight 6- to 9-inch diameter casings that would be drilled and grouted into the ground. The exposed portion of the pile group would be encased in a reinforced concrete cap from the top of the casings to a depth anywhere from one to eight feet below the ground surface, depending on the terrain.

Conductor installation would proceed in the same manner as the double-circuit tower installation. The equipment necessary for conductor installation would be large, heavy construction equipment that could only be brought in by truck. Some NFS roads could need maintenance or improvement to allow pulling and tensioning, but no new access or spur roads would be created for conductor installation on the helicopter-constructed towers. After project completion, any maintained access roads to helicopter fly yards/staging areas to would be reduced to 16 feet.

1.2.2. Addition of New 230 kV Circuit Between the proposed Haskell Canyon Switching Station and the existing Castaic Power Plant, LADWP proposes the addition of 12 miles of a new 230 kV transmission circuit onto existing Castaic – Olive 230 kV Transmission Line structures. The circuit would cross the unincorporated communities of Castaic and Saugus and the city of Santa Clarita. A total of 300 feet of BLM-managed public lands and four miles of NFS lands would be traversed; however, the new circuit would not require a new or additional ROW. This new circuit would be called Castaic – Haskell Canyon #4 and would utilize the same conductor (bundled 715.5 kcmil ―Starling‖ ACSS/AW [aluminum conductor steel supported/aluminum-clad steel wire]) as that proposed for the new 230 kV transmission line between Barren Ridge and Haskell Canyon Switching Stations.

The addition of a new circuit on existing towers would require many of the same construction activities associated with a new transmission line (refer to Appendix C for a description of each construction activity). However, all work would be within existing ROW and no new towers would be constructed. Some towers may need to be modified or reinforced to carry the additional weight of the new conductor. Specific towers requiring reinforcement would be determined following detailed design of the Project. Tower reinforcement would not alter the general design or the location of the structures. This process would generally include reinforced foundations or steel member replacements. Refer to Figure 1-1 for a map showing the location of the new 230 kV circuit.

1.2.3. Reconductoring of Existing Transmission Line LADWP proposes the reconductoring of 76 miles of the existing BR-RIN 230 kV transmission line with larger conductors from the Barren Ridge Switching Station to Rinaldi Substation. Four miles of BLM- managed public lands, 13 miles of National Forest System (NFS) lands, and 44 miles of private property would be traversed. The existing conductors (954/ 2,312 kcmil) would be replaced with a new 1,433.6 kcmil ―Merrimack‖ ACSS/TW/HS (aluminum conductor steel supported/trapezoidal wires/high strength) conductor. The new conductor would have a larger diameter that allows for greater electrical capacity.

The upgrade of the existing BR-RIN would also require many of the same activities of the new transmission line (surveying of right-of-way [ROW], rehabilitation of existing access and spur roads, clearing of ROW, conductor installation, and cleanup). Removal of the existing conductor would be used to string a pulling line, and this line would then be used to pull in the new conductor. All work would

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1.2.4. Construction of New Switching Station As a component of the BRRTP, LADWP proposes the construction of a new switching station in Haskell Canyon, south of the Angeles National Forest on LADWP-owned property at the convergence of several existing and proposed 230 kV transmission lines (the existing BR-RIN, the proposed double-circuit Barren Ridge – Haskell Canyon, existing Castaic – Northridge, Castaic – Sylmar, Castaic – Olive, and the proposed Castaic – Haskell Canyon). Refer to Figure 1-1 for the location of the new switching station.

The station would be approximately 500 feet by 600 feet to accommodate the necessary circuit positions, which are made up of equipment, such as steel support structures, circuit breakers, disconnect switches, and associated equipment, and a relay house and control house containing control and protective relaying equipment. The relay and control houses would each be approximately 30 feet long by 12 feet wide by 10 feet high and constructed of gray concrete block. The station yard would include a paved internal access road approximately 16 feet wide and would be enclosed by chain-link fencing with barbed-wire extension for security. The preliminary grading plan for the station is located in Appendix C.

Necessary pre-construction geotechnical investigation on-site would include six borings by a drill rig to investigate bedrock and soil stability and four cone penetration test locations after site grading to determine friction resistance for piers. The cone penetration test rig would be a small truck with a hydraulic ram assembly mounted on the back, which is used to push a 2.5-inch diameter cone into the ground to a depth up to 50 feet. Existing roads would be used to access the site.

Construction of the new Haskell Canyon Switching Station would consist of preconstruction surveys, clearing and grading of access roads, site grading and drainage development, installation of concrete foundations and steel support structures, installation of below- and above-ground electrical conduits for equipment power and control, installation of below- and above-grade grounding conductors, and installation of control and relay houses. Equipment required for station construction would include graders and excavators, backhoes, drill rigs, water trucks, scrapers, sheep’s foot compactors, front end loaders, concrete trucks, trucks, and flatbed trailers. Cranes, man-lifts, portable welding units, line trucks, and mechanic trucks would also be required. Construction would require an estimated 12 months with approximately 60 workers.

Site preparation work for the station would involve clearing and grading of access roads, clearing of the switchyard site, the cut and fill grading of the site, and placement and compaction of structural fill that would serve as a base for switching station facilities. The site would be graded to maintain current drainage patterns as much as possible. A 16-foot-wide paved road and a 100-foot by 100-foot gravel parking area would be required. The yard would be covered with crushed-rock aggregate. Native vegetation would be re-established where possible outside the switchyard fence.

Following site grading and development, reinforced concrete foundations would be installed to support the steel structures and electrical equipment and control facilities. It is estimated that 1,500 cubic yards of concrete would need to be delivered to the switching station site for the foundations. Foundation work would require approximately 180 trips to the site by 40-ton, 10-yard capacity concrete trucks over a 120- day working period. Subsequent to the foundation installation, trenches would be dug to facilitate placement of copper conductors for the station grounding mat.

Multiple transmission lines would be terminated into the switching station (i.e., the new and existing Barren Ridge – Haskell and Castaic – Haskell Canyon transmission lines) and would need support and require the installation of galvanized steel structures. An existing 115 kV transmission line may need to

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 14 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION be relocated around the proposed station. High-voltage bus work consisting of aluminum jumpers and tubing would be installed within the station.

1.2.5. Expansion of Existing Switching Station LADWP proposes expansion of the existing Barren Ridge Switching Station to the east side by 235 feet by 500 feet, for a total station size of 485 feet by 500 feet (approximately 5.6 acres). The expansion area of the station would include electrical structures and equipment for the addition of transmission lines, a material staging area, roadway within the station, and a drainage area. The preliminary design layout for the station may be found in Appendix C. Refer to Figure 1-1 for the location of the existing switching station.

Expansion of the existing switching station would be very similar to the construction of the Haskell Canyon Switching Station as described above. Expansion would consist of preconstruction surveys, site preparation and grading, installation of reinforced concrete foundations, installation of electrical conduits for equipment power and control, and installation of structures and equipment.

Necessary pre-construction geotechnical on-site investigation would include two test pits excavated by a backhoe to investigate soil density and settlement, and four cone penetration test locations on-site to determine friction resistance for piers. The cone penetration test rig would be a small truck with a hydraulic ram assembly mounted on the back, which is used to push a 2.5-inch diameter cone into the ground to a depth up to 50 feet. Existing roads would be used to access the site.

It is estimated that 700 cubic yards of concrete would need to be delivered to the switching station site for the foundations. Foundation work would require approximately 80 trips to the site by 40-ton, 10-yard capacity concrete trucks over a 90-day working period. Equipment required for station construction would include graders and excavators, backhoes, drill rigs, water trucks, scrapers, sheep’s foot compactors, front end loaders, concrete trucks, trucks, and flatbed trailers. Cranes, man-lifts, portable-welding units, line trucks, and mechanic trucks would also be required. An estimated eight months with approximately 60 workers would be required to expand the station.

1.2.6. Project-Wide Mitigation Measures To address potential impacts of the Proposed Project to multiple resource areas as discussed above, the following project-wide mitigation measure would be applied:

Three-Circuit Tower Mitigation (THREE-CIRCUIT) – A three-circuit lattice tower design would be implemented as described in Section 1.2.1 of this Technical Report, at the locations shown in Figure 1-7, Three-Circuit Tower Mitigation Map.

Helicopter Mitigation (HELICOPTER) – Helicopter Mitigation shall be implemented, as described in Section 1.2.1 of this Technical Report, in steep areas of the Angeles National Forest where access is limited. For Alternatives 1 and 2a, implementation would occur at the locations shown on Figure 8-2, Identified Helicopter Mitigation Map. During final design of the Project, areas other than those shown on Figure 8-2, including Alternatives 2 and 3, may potentially require helicopter construction of the towers. This determination would generally be made where tower sites have no existing access roads within 300 feet and slopes are greater than 25 percent. Final identification of these tower sites would be determined and agreed upon by USFS, BLM and LADWP.

1.2.7. Construction Work Force and Schedule The NEPA Record of Decision and CEQA Notice of Determination (anticipated in the early part of 2012) must be made before construction could begin. Therefore, construction of the BRRTP is anticipated to

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 15 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION begin no sooner than summer 2012, with a target in-service date of early 2015. These dates are subject to change based on actual completion of design.

The following construction estimates were based on preliminary engineering and the number of workers and construction duration values are estimates; therefore, they are subject to change based on final engineering and design. The new double-circuit 230 kV transmission line from the Barren Ridge Switching Station to the proposed Haskell Canyon Switching Station would require 12.5 months and 134 workers. The installation of a 230 kV circuit on existing double-circuit towers from the Castaic Power Plant to the proposed Haskell Canyon Switching Station would require a month and a half and 35 workers. The upgrade and reconductoring of the existing BR-RIN would require eight months and 155 workers. The construction of a new 400-foot by 600-foot Haskell Canyon Switching Station would require 12 months and 60 workers. The expansion of the existing Barren Ridge Switching Station would require eight months and 60 workers.

The BRRTP components are anticipated to be constructed in the staggered sequence illustrated below in Tables 1-1 and 1-2. The construction of all Project components would take approximately two years and 447 total workers, with 173 workers at the peak of construction. Table 1-2 summarizes the BRRTP’s anticipated construction workforce and schedule based on the most current information available. To allow for any delays in the Project, three weeks of float time were included for the new 230 kV transmission line and reconductoring efforts, and an additional two weeks of float time were included for the stringing of the second circuit between Castaic Power Plant and Haskell Canyon.

TABLE 1-1. ANTICIPATED CONSTRUCTION SEQUENCE

PROJECT COMPONENT ANTICIPATED CONSTRUCTION SEQUENCE Expansion of Barren Ridge Switching Weeks 8 – 73 Station New Haskell Canyon Switching Station Weeks 1 – 67

New 230 kV Transmission Line Weeks 42 – 113

Reconductor BR-RIN Weeks 55 – 88 Weeks Addition of 230 kV Circuit 51 – 56

TABLE 1-2. CONSTRUCTION WORKFORCE AND SCHEDULE PEAK # OF CONSTRUCTION CONSTRUCTION TOTAL # OF WORKERS PROJECT COMPONENT (START AND END DURATION WORKERS AT ANY GIVEN WEEKS) (MONTHS) TIME Expansion of Barren Ridge Switching 8 – 73 15 60 38 Station New Haskell Canyon Switching Station 1 – 67 15.4 63 38 New 230 kV Transmission Line 42 – 113 16.5 134 131 Reconductor BR-RIN 55 -88 9 155 120 Addition of 230 kV Circuit 51 – 56 1.5 35 35 447 Total 173* Peak ALL COMPONENTS Weeks 1 – 113 26.1 months Workers Workers *The value represents the total for the staggered construction of the Project components; it is not reflective of the sum of all the components.

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2.0 REGULATORY FRAMEWORK

Primary state guidance relating to principal seismic hazards evaluated in this report is contained in the 1990 Seismic Hazards Mapping Act and 1994 Alquist-Priolo Earthquake Fault Zoning Act (originally enacted in 1972). The Seismic Hazards Mapping Act focuses on potential seismic hazards related to strong ground shaking, liquefaction, and seismically induced landslides. Under provisions in the act, the State is charged with designating and mapping areas at risk for these seismic hazards and the maps and associated reports are to be used by cities and counties in preparing their general plans and adopting land use policies to reduce and mitigate potential hazards to public safety. The California Geological Survey (CGS) has provided Seismic Hazard Zones maps for some quadrangles located in the southern part of the proposed Project area, and these maps are incorporated into this study for evaluation of liquefaction hazard zones and earthquake-induced landslide hazard zones. Some quadrangles in the Project area have not yet been mapped by the State.

Under the Alquist-Priolo Earthquake Fault Zoning Act, the state is charged with delineating ―Earthquake Fault Zones‖ (formerly known as Alquist-Priolo Special Studies Zones) along known active, well-defined faults in California. Cities and counties affected by the zones are to regulate certain development projects for sites within the zones until geologic investigations demonstrate that the sites are not threatened by surface displacement from future faulting. The CGS produces maps delineating Earthquake Fault Zones for quadrangles located in the proposed Project area, and these maps are incorporated into the study for evaluation of potential surface fault rupture related to the active Earthquake Fault Zones in the Project area.

Regulatory agencies responsible for overseeing design and construction of the proposed BRRTP would refer to Seismic Hazards Mapping Act and Alquist-Priolo Earthquake Fault Zoning Act guidelines for evaluation of potential seismic hazards that may affect the Project. In addition to the potential seismic impacts under these guidelines, other potential geologic impacts that may affect the Project would be evaluated during the design and construction phases of the Project, and presented to the regulatory agencies for consideration, as appropriate. Other potential geologic impacts that have been assessed in this preliminary geotechnical evaluation include landslides and mudflows, soil erosion, settlement, expansive soils, corrosive soils, groundwater and dam inundation.

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3.0 PROJECT AREA OVERVIEW

The Project study area is bounded by Interstate 5 and the ANF to the west, the Tehachapi Mountains and Piute Mountains to the north, State Highway 14 and the San Gabriel Mountains to the east, and the San Fernando Valley area of Los Angeles to the south (Figure 1). Main physiographic features of the Project area include the Mojave Desert and Antelope Valley area; the San Andreas Rift Zone, which strikes northwesterly through the middle of the Project area; the steep mountainous terrain in the ANF; and the valley areas in the cities of Santa Clarita and San Fernando.

The Mojave Desert and Antelope Valley area is generally comprised of relatively gentle to moderate topographic gradients. Elevations in this part of the Project area range from 2,400 to 3,000 feet above mean sea level (MSL) on the valley floor, and up to 3,200 feet MSL along the flanks of the Tehachapi Mountains. The proposed expanded Barren Ridge Switching Station, proposed Segments A, B, C, E, F, 115th, and the northern portions of Segments D, G, H and I are situated in this part of the Project area (Figure 1).

The San Andreas Rift Zone, associated with movement of the active San Andreas fault, comprises a linear trough of elongate valleys and ridges that crosses about the middle of the Project area oriented in a northwest direction. The rift zone essentially forms a boundary between the Mojave Desert/Antelope Valley area and the ANF/Sierra Pelona mountainous area. Segment D and the northern portion of Segments G, H and I cross the San Andreas Rift Zone. Segment D crosses the rift zone in the western part of the Project study area. Segments G, H and I cross the San Andreas Rift Zone in the Leona Valley in the east part of the study area (Figure 1). The rift zone in the Leona Valley is bounded by Portal Ridge and Ritter Ridge on the northeast. Topographic gradients in this area of the Project range from gentle on the floor of the rift zone trough and Leona Valley to steep on the flanking hillsides including the Portal Ridge and Ritter Ridge areas. Elevations in the San Andreas Rift Zone, Portal Ridge and Ritter Ridge areas range from 3,000 to 3,600 feet MSL.

The ANF part of the Project area generally comprises mountainous areas of gentle to very steep topographic gradients and includes the Sierra Pelona, Liebre Mountain and Bald Mountain. Northeast- trending canyons in the ANF part of the Project area include Liebre Gulch, San Francisquito Canyon, Bouquet Canyon, Mint Canyon, Haskell Canyon and Soledad Canyon. Elevations in the ANF part of the study area range from 1,300 feet MSL in canyon bottoms in the Santa Clarita area, to 4,500 feet MSL on the ridgelines in the Sierra Pelona. Segments G, H, I, J, and the southern portion of Segment D are situated in this part of the Project area. The proposed Haskell Canyon Switching Station is located in this part of the Project area at the northern end of Haskell Canyon (Figure 1).

The southern part of the Project area is situated between the Santa Clarita Valley and San Fernando Valley, which comprise areas of relatively gentle to moderate topographic gradients, and includes steep topographic gradients in the San Gabriel Mountains between these valleys. Elevations range from 1,300 feet MSL to 1,500 feet MSL in the Santa Clarita valley area; from 1,500 feet MSL to 2,300 feet MSL in the San Gabriel Mountains between the valleys; and from 1,000 feet MSL to 1,500 feet MSL in the northern San Fernando Valley. Segment K for the proposed reconductoring of the existing 230kV line from the new Haskell Canyon location to Rinaldi is located in this part of the Project area.

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4.0 INVENTORY METHODS

To develop a geologic inventory for the proposed BRRTP, this preliminary geotechnical evaluation has included review of soil, geologic and seismic background information and field reconnaissance for assessment of potential geologic and seismic hazards and potential geologic impacts associated with implementation of the Project in the study area. A review of geotechnical background data, geologic maps, topographic maps, regional fault maps, seismic data, soil data, groundwater data, GIS data, and aerial photography was performed to assess the general geologic and seismic conditions within the Project study area and underlying the proposed route corridors and switching stations. Field reconnaissance was performed of accessible areas of the Project components to observe general geologic site conditions, map pertinent geologic features, and check the overall aerial geology presented on geologic maps. Compilation and analysis of the data obtained were performed to evaluate potential Project impacts and develop recommendations for mitigation, as appropriate.

Geologic maps, data and literature published by the CGS, formerly the California Division of Mines & Geology (CDMG), have been incorporated as part of this study for evaluation of the Project area geology, distinctive geologic features, faults, potential liquefaction hazard zones and earthquake-induced landslide hazard zones, mapped landslide or mudflow areas, and groundwater. Data and information from the Southern California Earthquake Center (SCEC) have been utilized for information related to faults. Groundwater data from the California Department of Water Resources (CDWR), where available, have been utilized for evaluation of groundwater levels in the Project study area. Regulations within the California Building Code (CBC) are considered for potential design mitigation recommendations. Geotechnical-related portions of the California Environmental Quality Act (CEQA) have been utilized as a guideline for this evaluation.

Seismic data published by the United States Geological Survey (USGS) have been incorporated in this study for evaluation of potential ground shaking levels in the Project study area. GIS data for potential ground shaking levels were utilized. Topographic maps published by the USGS have been reviewed as part of this study for evaluation of elevations and topographic gradients in the Project area. Soil data from the United States Department of Agriculture (USDA) National Resource Conservation Service (NRCS) have been utilized to evaluate USDA soil classifications, potential soil erosion, expansive soils and corrosive soils. Geotechnical-related portions of the Safety Elements of the Los Angeles County General Plan and Kern County General Plan have been incorporated into this study for evaluation of potential subsidence, and dam failure and seiche inundation hazard areas. Background documents reviewed are presented in the References.

Field reconnaissance of the proposed segments and switching stations sites was performed to supplement the background literature study for this evaluation. Field reconnaissance was limited to portions of segments in the Project area accessible by vehicle on existing transmission line and other access roads. The visual reconnaissance was made to observe general geologic site conditions and topographic conditions, observe conditions of existing transmission line improvements, map pertinent geologic features, and check the general geologic mapping presented on geologic references. Observations were made of the siting area for the proposed Haskell Canyon Switching Station and of the proposed expanded Barren Ridge Switching Station. Field observations were generally made in accessible areas within an approximate ½-mile-wide study corridor along the proposed routes. The field reconnaissance was further supplemented by aerial (helicopter) reconnaissance photographs and notes provided by LADWP geologists for inaccessible portions of some segments of the Project.

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5.0 AFFECTED ENVIRONMENT

5.1 REGIONAL GEOLOGIC SETTING The Project study area is located within two geomorphic regions, or ―provinces,‖ characterized by the morphology of the landforms, the general type and age of the geologic materials, and by the tectonic- structural features of the geology in the region. The Transverse Ranges Geomorphic Province and Mojave Desert Geomorphic Province that include the study area are divided by the northwest-trending San Andreas fault zone. The Antelope Valley, Mojave Desert and Barren Ridge part of the study area northeast of the San Andreas fault is located in the western corner of the Mojave Desert Province. The part of the study area southwest of the San Andreas fault, including the ANF, Sierra Pelona, and the cities of Santa Clarita and San Fernando, is within the Transverse Ranges Province.

The Mojave Desert Geomorphic Province is characterized by mountain ranges and hills of moderate relief that are partially buried and separated by broad alluviated basins like the Antelope Valley (Norris and Webb, 1990). This province is bounded in the study area by the San Andreas fault on the southwest and by the Garlock fault on the northwest, forming a triangular-shaped region on the west side of this province. The Mojave Desert Province extends east from the study area. The Transverse Ranges Geomorphic Province is characterized by east-west trending mountain ranges and fault systems (Norris and Webb, 1990). The province is bounded on the northeast by the San Andreas fault, and extends west and south from the study area.

5.2 STUDY AREA GEOLOGIC SETTING The mountain ranges and hills of the Project study area are comprised primarily of Tertiary age (2 to 65 million years old) marine and non-marine sedimentary and volcanic rocks; Mesozoic era (65 to 245 million years old) granitic rocks; and Paleozoic era (245 to 570 million years old) metamorphic and granitic rocks including schist, gneiss and limestone. Younger Quaternary age (last 1.6 million years) alluvium and other sediments underlie low-lying valley and canyon bottoms, and much of the Mojave Desert and Antelope Valley parts of the study area. A regional geologic map of the study area is shown on Figure 2.

The older, pre-Tertiary age crystalline basement rocks typically comprise granite, quartz monzonite, gabbro, schist, gneiss, and other igneous and metamorphic rocks. Younger Tertiary age volcanic and sedimentary formations of marine and non-marine origin that overlie the basement rocks contain units of sandstone, siltstone, shale, conglomerate, and undifferentiated pyroclastic and intrusive volcanic rocks. Younger Quaternary age alluvium and other deposits overlie the bedrock in the Mojave Desert and Antelope Valley, and other valleys, canyon bottoms and low-lying drainage areas in the study area.

The Quaternary deposits are generally subdivided into two stratigraphic units according to relative age: older Pleistocene (11,000 to 2 million years ago) age deposits, and younger Holocene deposits (last 11,000 years). Older Pleistocene age alluvial deposits generally consist of gravel, sand, silt, and clay that is moderately to well consolidated and often slightly cemented. These materials include older alluvial fan deposits in the Mojave Desert and Antelope Valley, continental terrace deposits, and older lacustrine (lake) or playa deposits. Holocene deposits typically consist of relatively young, poorly consolidated or unconsolidated silt, sand and gravel alluvium, and are anticipated to be present in the study area in washes, valley bottoms, and lakebeds. The Holocene deposits can also include eolian (wind-blown) sands, colluvial (slopewash) deposits, residual soils, and agricultural and fill soils from farming, grading or other man-made activities in the Project area.

In general, the distribution of geologic units in the Project study area, as shown on Figure 2, is such that much of the northern half of the Project study area in the Antelope Valley and Mojave Desert is underlain by Quaternary alluvial sediments. Much of the southern half of the Project study area in the mountainous ANF and Sierra Pelona is underlain by older Tertiary and pre-Tertiary rock formations, with the exception

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TABLE 1 – PRINCIPAL GEOLOGIC UNITS IN THE PROJECT STUDY AREA

GEOLOGIC SYMBOL1 GEOLOGIC UNIT DESCRIPTION Qs Dune Sand Recent wind-blown sand (eolian) deposits. Qa Alluvium Unconsolidated, poorly sorted alluvial clay, silt, sand and gravel sediments. Includes fan, flood plain, and streambed deposits; and includes mixture of playa clay and wind-blown sand in some desert areas. Qpc Plio-pleistocene Varied sedimentary rocks of non-marine origin including shale, siltstone, non-marine sandstone, conglomerate and breccia. Tc, Mc, Oc Tertiary non-marine Varied sedimentary rocks of non-marine origin including clay shale, mudstone, siltstone, sandstone, fanglomerate and breccia. P, M, E, Ep Tertiary marine Varied sedimentary rocks of marine origin including shale, mudstone, siltstone, sandstone, and conglomerate. Ti, Tv, Tvp Volcanic rocks Undifferentiated volcanic rocks including rhyolite, andesite, basalt, and pyroclastic rocks; and intrusive volcanic (hypabyssal) rocks of similar composition. gr-m Granitic and Undifferentiated gneisses and granitic rocks. metamorphic rocks gb, grMz, grPz, grpC Granitic rocks Granitic rocks including quartz monzonite, granodiorite, quartz diorite, diorite, gabbro, and anorthosite. ls/PZ Paleozoic Sedimentary and metasedimentary limestone, dolomite and marble. Lenses of marble in granitic and metamorphic rocks in the Tehachapi Mtns. sch Schist Highly foliated, mica-rich schist (Pelona Schist). m Metasedimentary Biotite gneiss, mica schist, quartzite and hornfels. rocks pC Gneiss Coarse and fine augen gneisses, amphibolite, hornfels, diorite and granite gneiss. Notes: 1 Symbol used on Figure 2.

5.3 SEISMICITY The Project study area is situated within a seismically active region of southern California, and numerous active and potentially active faults have been mapped within or adjacent to the study area. As defined by the CGS, an active fault is one that has had surface displacement within Holocene time (roughly the last 11,000 years). Potentially active faults are those that show evidence of surface displacement during Quaternary time (roughly the last 1.6 million years) but for which evidence of Holocene movement has not been established. An inactive fault is one that has not shown evidence of surface displacement during Quaternary time.

The approximate locations of the principal active faults in the region and their geographic relationship to the study area are shown on Figure 3. Table 2 lists nearby principal faults, the maximum moment magnitude (Mmax), the fault type, the slip rate, the fault source type, and significant historic earthquakes that have occurred on the faults.

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TABLE 2 – PRINCIPAL REGIONAL ACTIVE AND POTENTIALLY ACTIVE FAULTS

APPROXIMATE MAXIMUM SIGNIFICANT DISTANCE TO MOMENT SLIP RATE FAULT FAULT TYPE2 HISTORIC NEARBY SEGMENT MAGNITUDE (mm/yr) 2 EARTHQUAKES3 (SEGMENT) (miles) 1 (Mmax ) 2 Big Pine 14.5 (D) 6.9 SS 0.8 - Clamshell – Sawpit 28.0 (I) 6.5 R 0.5 M5.8 Sierra Madre, Canyon 6/28/91 Garlock (West) Fault 0.0 (A) 7.3 SS 6.0 - Zone Helendale-South 26.0 (A) 7.3 SS 0.6 - Lockhart Lenwood-Lockhart-Old 16.0 (A) 7.5 SS 0.6 - Woman Springs Malibu-Santa Monica- 14.0 (K) 6.7 RO 0.4 - Hollywood –Raymond Fault Zone4 Northridge (East Oak 14.5 (D) 7.0 R 1.5 M6.7 Northridge, Ridge) 1/17/94 Pleito Thrust 14.5 (D) 7.0 R 2.0 - San Andreas 0.0 (D, G, H, I) 7.4 SS 30 M7.9 Fort Tejon, (Mojave - 1857 Rupture) 1/9/1857 San Cayetano 10.0 (D) 7.0 R 6.0 - San Gabriel 1.0 (D) 7.2 SS 1.0 - San Fernando Fault 0.0 (K) 6.8 R 5.0 M6.6 San Fernando, Zone2 2/9/71 1.0 (K) 6.7 R 5.0 M6.6 San Fernando, Santa Susana 2/9/71 Santa Ynez (East) 11.0 (D) 7.1 SS 2.0 - Sierra Madre 7.0 (K) 7.2 R 2.0 - Sierra Madre (San 5.0 (K) 6.7 R 2.0 - Fernando) Southern Sierra Nevada 4.0 (A) 7.3 N 0.1 - Verdugo 3.0 (K) 6.9 R 0.5 - 24.5 (A) 7.3 RO 2.0 M7.5 Kern County, White Wolf 7/21/52 Notes: References: SS – Strike Slip R – Reverse 1 Jennings, 2010. 3 SCEC, 2004 N -- Normal RO – Reverse-Oblique 2 Cao, et al, 2003 4 Dolan, et al, 2000a, 2002

Principal active faults in the region that may affect the site are described below:

San Andreas Fault Zone The San Andreas fault zone has long been recognized as the dominant seismotectonic feature in California. This active, right-lateral, strike-slip fault is over 700 miles long and strikes northwest through the state from the Gulf of California to north of San Francisco. Two of California’s three largest historic earthquakes, the 1906 San Francisco earthquake and the 1857 Forth Tejon earthquake, occurred along the San Andreas fault (SCEC, 2004). The slip rate of the fault is estimated to be 30 millimeters (mm) per year (Cao, 2003). The fault is considered capable of producing earthquakes in excess of Mmax 7.4, and the average frequency of earthquakes along this segment of the San Andreas fault is 140 years (SCEC, 2004). The San Andreas fault crosses Segments D, G, H and I through the middle of the Project study area, oriented in a northwesterly direction (Figure 3).

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 22 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION Garlock Fault Zone (West) The Garlock fault zone is a prominent fault feature in southern California and strikes northeast across the northern part of the Mojave Desert province. Although this fault has not produced large earthquakes historically, geomorphic and stratigraphic evidence indicates that it has done so in the past. The Garlock (West) fault is considered capable of generating about a Mmax 7.3 earthquake. A portion of the Garlock fault zone near the Project study area ruptured due to the 1952 Kern County Earthquake that occurred on the White Wolf Fault (SCEC, 2004). A total of about 30 to 40 miles of left-lateral, strike slip has been documented across the Garlock (West) fault, and the slip rate is estimated to be 6 mm per year. The Garlock (West) fault zone crosses Segment A at the northern end of the segment near Barren Ridge.

San Fernando Fault Zone The San Fernando fault zone is a zone of thrust faulting and ground rupture areas related to the 1971 San Fernando earthquake, and is located in the Sunland and San Fernando area of the San Fernando Valley (SCEC, 2004). The zone is 10 miles long, has an estimated slip rate of 5 mm per year, and is considered capable of generating about a Mmax 6.8 earthquake (SCEC, 2004). The San Fernando fault zone crosses the southern end of Segment K in the San Fernando area.

Santa Susana Fault The Santa Susana fault is a thrust fault 23 miles long located near the communities of Piru, Sylmar, and San Fernando. A short segment of the fault ruptured slightly during the 1971 San Fernando earthquake (SCEC, 2004). The Santa Susana fault is considered capable of generating about a Mmax 6.7 earthquake. The slip rate of the fault is estimated to be 5 mm per year. The Santa Susana fault is located near the south end of the Project study area west of the Rinaldi substation.

San Gabriel Fault Zone Segments of the San Gabriel fault zone are described as potentially active, and a portion of the fault between Castaic and Saugus is described as active (Jennings, 1994). This right-lateral, strike-slip fault is considered capable of producing a Mmax 7.2 earthquake. The San Gabriel fault has a total length of 87 miles, and the slip rate of the fault is estimated to be 1 mm per year. The San Gabriel fault zone crosses Segment K.

Sierra Madre Fault Zone The Sierra Madre fault zone is composed of a series of active reverse faults. The 35-mile-long fault zone is located between the cities of Sunland and Azusa along the foothills of the San Gabriel Mountains. The Sierra Madre fault is considered capable of generating about a Mmax 7.2 earthquake. The slip rate of the fault is estimated to be 2 mm per year. The Sierra Madre fault is located southeast of the Project study area.

White Wolf Fault The White Wolf fault is an active, left-lateral reverse fault located northwest of the Project study area near the community of Tehachapi. The White Wolf fault was the source of one of the largest earthquakes in Southern California history, the 1952 M 7.5 Kern County earthquake (SCEC, 2004). The Tehachapi area reportedly experienced extensive property damage due to the 1952 Kern County earthquake (Kern County, 2005). The White Wolf fault is considered capable of generating about a Mmax 7.5 earthquake. The fault is 37 miles in length and has an estimated slip rate of 2 mm per year.

Pleito Thrust Fault Zone The Pleito Thrust fault zone is a south-dipping, active thrust fault that is part of a complex zone of thrust faults and folds which mark part of the southern end of the Central Valley of California. The Pleito thrust may be connected at depth with the nearby, and similar, Wheeler Ridge fault. At the eastern end of the

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 23 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION fault, it may dive below the surface as a blind thrust, forming the northern scarp of the Tehachapi Mountains (SCEC, 2004). The Pleito thrust is considered capable of generating about a Mmax 7.0 earthquake, and has an estimated slip rate of 2.0 mm per year (Cao, 2003). The Pleito thrust fault zone is 28 miles in length is located west of the Project study area.

Lenwood-Lockhart-Old Woman Springs Faults The Lenwood, Lockhart, and Old Woman Spring faults are right-lateral, strike-slip faults that form a connected, fairly complex, fault system 99 miles long (SCEC, 2004). The Lenwood-Lockhart-Old Woman Spring fault system is considered capable of generating about a Mmax 7.5 earthquake. The slip rate of the fault is estimated to be 0.6 mm per year (Cao, 2003). Portions of this fault system located in the Mojave Desert east of Barren Ridge are considered active (Jennings, 1994).

Helendale-South Lockhart Faults The active Helendale fault is a right-lateral, strike-slip fault about 56 miles in length and may form a roughly continuous fault system with the active South Lockhart fault located east of Barren Ridge in the study area (SCEC, 2004). This fault system is considered capable of producing a Mmax 7.3 earthquake. The slip rate of the fault is estimated to be 0.6 mm per year (Cao, 2003). The Helendale-South Lockhart faults are located in the Mojave Desert east of the Project study area.

San Cayetano Fault The San Cayetano fault is a thrust fault 28 miles long located near the communities of Piru, Fillmore, and Ojai. The San Cayetano fault is considered capable of generating about a Mmax 7.0 earthquake. The slip rate of the fault is estimated to be 6 mm per year. The San Cayetano fault is located west of the Project study area.

Malibu-Santa Monica-Raymond Fault Zone The Malibu Coast, Santa Monica, Hollywood, and Raymond faults are considered a fault zone that is a subsystem of the Transverse Ranges Southern Boundary fault system (Dolan, et al, 2000). The fault zone extends sub-parallel to the Malibu coastline easterly along the south side of the Santa Monica Mountains through Malibu, Santa Monica, West Los Angeles, and Hollywood. The fault system exhibits reverse left- lateral movement and is considered capable of generating earthquakes ranging from M 6.4 to 6.7 in the Project area (Cao, 2003).

5.4 DATA INVENTORY RESULTS - SEGMENTS 5.4.1. Geologic Resources Soils Soils are present at the ground surface along the majority of the proposed Project segments except in locations where rock formations are exposed. In a general sense, deeper soils are present in the valleys and other low-lying areas of the Project, and shallow soils are present in the mountainous parts of the Project study area. The soils underlying the proposed Project segments are comprised of variable material types from gravel and sand to silt and clay, and are generally reflective of the underlying geologic unit, extent of weathering, degree of slope, and the degree of human modification. The proposed Project segments traverse varied terrain and land areas comprised of undeveloped desert and mountain areas, agricultural land, developed rural properties, and developed urban areas consisting of industrial, commercial and residential uses.

In order to inventory the soils underlying the Project segments, data from the NRCS was evaluated. Soil surveys from the NRCS utilized for the evaluation included Kern County, Southeastern Part (CA670), Antelope Valley Area (CA675), ANF (CA776), and Los Angeles County, West San Fernando Valley (CA676). More than 125 soil types are mapped underlying the proposed Project segments, and an

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 24 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION inventory of these individual soils, including a general description of the soil, the soil erodibility potential, shrink-swell potential, and corrosion potential, is provided for the segments on a 1/10th mile basis on the USDA Soil Table in Appendix B. A summary of NRCS U.S. General Soil Types (soil families) for each segment and for the switching stations is presented in Table 3, and is shown on the Regional Soils Map on Figure 4.

TABLE 3 – SUMMARY OF U.S. DEPARTMENT OF AGRICULTURE U.S. GENERAL SOIL TYPES1 SEGMENT/LOCATION U.S. GENERAL SOIL TYPES A Wasco-Rosamond-Cajon (s1024) Tunis-Trigger-Torriorthents-Rock Outcrop (s766) Neuralia-Garlock-Cajon-Alko (s769) B Wasco-Rosamond-Cajon (s1024) Neuralia-Garlock-Cajon-Alko (s769) Rosamond Variant-Rosamond Playas-Gila-Cajon Variant-Cajon (s768) Ramona-Hanford-Greenfield (s1009) C Wasco-Rosamond-Cajon (s1024) Neuralia-Garlock-Cajon-Alko (s769) Ramona-Hanford-Greenfield (s1009) D Ramona-Hanford-Greenfield (s1009) Oak Glen-Gullied Land-Gorman-Gaviota-Cushenbury (s1034) Gaviota-Cieneba-Capistrano-Caperton (s1055) Sobrante-Exchequer-Cieneba (s1054) Xerofluvents-Salinas-Pico-Mocho-Metz-Anacapa (s909) E Wasco-Rosamond-Cajon (s1024) Ramona-Hanford-Greenfield (s1009) F Ramona-Hanford-Greenfield (s1009) 115th Ramona-Hanford-Greenfield (s1009) Gaviota-Cieneba-Capistrano-Caperton (s1055) G Ramona-Hanford-Greenfield (s1009) Gaviota-Cieneba-Capistrano-Caperton (s1055) Wilshire-Soboba-Oak Glen-Avawatz (s1047) Stonyford-Rock Outcrop-Chilao (s1056) Sobrante-Lodo (s1057) Sobrante-Exchequer-Cieneba (s1054) 2a Gaviota-Cieneba-Capistrano-Caperton (s1055) H Gaviota-Cieneba-Capistrano-Caperton (s1055) Wilshire-Soboba-Oak Glen-Avawatz (s1047) Sobrante-Lodo (s1057) Sobrante-Exchequer-Cieneba (s1054) I Ramona-Hanford-Greenfield (s1009) Gaviota-Cieneba-Capistrano-Caperton (s1055) Sobrante-Lodo (s1057) Pismo-Etsel Family-Cieneba-Caperton (s1059) Xerofluvents-Salinas-Pico-Mocho-Metz-Anacapa (s909) Sobrante-Exchequer-Cieneba (s1054) J Sobrante-Exchequer-Cieneba (s1054) Xerofluvents-Salinas-Pico-Mocho-Metz-Anacapa (s909)

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SEGMENT/LOCATION U.S. GENERAL SOIL TYPES K Sobrante-Exchequer-Cieneba (s1054) Xerofluvents-Salinas-Pico-Mocho-Metz-Anacapa (s909) Pismo-Etsel Family-Cieneba-Caperton (s1059) Zamora-Urban Land-Ramona (s1033) Urban Land-Sorrento-Hanford (s1026) Haskell Canyon Switching Station Sobrante-Exchequer-Cieneba (s1054) Barren Ridge Switching Station Wasco-Rosamond-Cajon (s1024) Notes: 1 USDA, 2006.

Distinctive Geologic Features This geologic resource refers to the potential existence of distinctive, prominent geologic features, which may have beneficial aesthetic or scientific characteristics. Distinctive geologic features can include unique marker beds, scenic rock formations or significant outcrops. In addition to the positive aesthetic characteristics of distinctive rock formations, these features provide access for geologists and the public to observe and study the underlying rock formation or geologic structure of an area where it may otherwise be concealed by soil cover.

Based on background review and limited field reconnaissance, there are distinctive geologic features that are present in some of the rock formations in the Project study area. Geologic features traversed by the proposed segments in the BRRTP study area that are considered distinctive include white tuff (volcanic ash) marker beds that are mapped in the Bouquet Canyon/Vasquez Canyon area along Segment I. The white tuff marker beds that are present along Segment I are considered a distinctive aesthetic feature due to their white color and the characteristic formation that outcrops (juts out of the ground) in the Bouquet Canyon/Vasquez Canyon bottom. This rock unit is also reported to contain vertebrate fossils. The evaluation of this rock unit as a paleontological resource is provided in the paleontological technical report.

Rock formations in the Project study area are present in the southern part of Segment D, and in Segments G, 2a, H, I, J, and portions of Segment K. The majority of these geologic formations contains more common rock outcrops, exposed road cuts and soil-covered areas, and is not considered highly distinct. However, distinctive geologic features may be present in limited areas of some rock formations in the Project study area not indicated on geologic maps or observed during field reconnaissance. The Mojave Desert and Antelope Valley portions of the Project, and other low-lying valley areas with alluvium and soil cover do not comprise rock formations at the ground surface and do not contain distinctive geologic features.

Distinctive geologic features were not observed at the location of the proposed expanded Barren Ridge Switching Station and were not observed at the site of the proposed Haskell Canyon Switching Station. A summary of distinctive geologic features is presented in Table 4, and is provided for the corridor segments on a 1/10th mile basis on the Impact Assessment Table in Appendix A.

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TABLE 4 – SUMMARY OF DISTINCTIVE GEOLOGIC FEATURES

SEGMENT DISTINCTIVE GEOLOGIC FEATURES 1 A None B None C None D None E None F None 115th None G None 2a None H None I White tuff marker beds from mileposts 27.0 to 27.1, 28.6 to 28.9 J None K None Notes: 1 Dibblee, 1997c, 1997f, 2002b; field observations.

5.4.2. Geologic and Seismic Hazards Surface Fault Rupture Surface fault rupture is the offset or rupturing of the ground surface by relative displacement across a fault during an earthquake. Evaluation of the potential hazard of surface fault rupture is based on the concepts of recency and recurrence of faulting along existing faults. In general, the more recent the faulting, the higher the probability for future faulting (Allen, 1975). Faults of known historic activity during the last 200 years, as a class, have a higher probability for future activity than faults classified as Holocene age (last 11,000 years) and a much higher probability of future activity than faults classified as Quaternary age (last 1.6 million years). However, it should be kept in mind that certain faults have recurrent activity measured in tens or hundreds of years whereas other faults may be inactive for thousands of years before being reactivated. The magnitude, sense, and nature of fault rupture also vary for different faults or even along different strands of the same fault. Even so, future faulting generally is expected to recur along pre-existing faults (Bonilla, 1970). The development of a new fault or reactivation of a long-inactive fault is relatively uncommon and generally is not a consideration in project development.

There is a probability for surface fault rupture to occur across the proposed Project segments along the more recent, historically active faults, particularly the active San Andreas fault zone, Garlock fault zone and San Fernando fault zone. The segment of the San Andreas fault that ruptured during the 1857 Fort Tejon earthquake is located in the Project study area. Ground surface offset as much as 30 feet was reported across the fault due to that earthquake. Other active and potentially active faults in the Project study area may also have potential for surface rupture due to seismic activity. During an earthquake on these active or potentially active faults within the Project area, potential surface rupture of the fault may result in relative displacement of the ground across the fault surface.

Some proposed segments of the BRRTP are located within a State of California Earthquake Fault Zone for the potential for ground surface rupture due to active faults. Earthquake Fault Zones within the proposed Project area are related to active faults that include the San Andreas fault zone crossed by segments D, G, H and I; the Garlock (West) fault zone crossed by Segment A near Barren Ridge; and splays of the San Fernando fault zone under Segment K located in the San Fernando Valley. The proposed Haskell Canyon and expanded Barren Ridge switching stations are not located in an Earthquake Fault Zone. Earthquake Fault Zones within the Project study area are shown on Figure 5.

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 27 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION A summary of Earthquake Fault Zones is presented in Table 5, and is provided for the corridor segments on a 1/10th mile basis on the Impact Assessment Table in Appendix A.

TABLE 5 – SUMMARY OF EARTHQUAKE FAULT ZONES

SEGMENT EARTHQUAKE FAULT ZONES1 A Garlock Earthquake Fault Zone from milepost 0.6 to 2.0. B None C None D San Andreas Earthquake Fault Zone from milepost 20.2-21.7 E None F None 115th None G San Andreas Earthquake Fault Zone from milepost 5.3 to 6.2. 2a None H San Andreas Earthquake Fault Zone from milepost 3.8 to 4.6. I San Andreas Earthquake Fault Zone from milepost 7.6 to 9.1. J None K San Fernando Earthquake Fault Zones from milepost 11.0 to 11.7 and from milepost 13.7 to 15.4. Notes: 1 Hart and Bryant, 1997 (formerly Alquist-Priolo Special Studies Zones).

Seismic Ground Shaking Seismic ground shaking is the response of the surface to the passing of earthquake wave fronts radiating from the focus of the earthquake. The period of shaking corresponds with the passage of the seismic wave through the site. Earthquake events from one of the regional active or potentially active faults within or near the study area could result in strong ground shaking which could affect the Project study area. The level of ground shaking at a given location depends on many factors, including the size and type of earthquake, distance from the earthquake, and subsurface geologic conditions. Disregarding local variations in ground conditions, the intensity of shaking at different locations within the study area can generally be expected to decrease with distance away from an earthquake source. The size and type of construction also affects how particular structures perform during ground shaking.

In order to evaluate the level of ground shaking that might be anticipated along the proposed Project segments due to the extent of the area, estimated peak horizontal ground acceleration (PGA) data available from the USGS was reviewed (USGS, 2002). These data indicate that the Project study area is located in an area where PGA ranging from 0.25g to 0.80g (25 to 80 percent of the acceleration due to gravity) would be anticipated during an earthquake. Higher ground acceleration levels are attributable to higher levels of ground shaking. Estimated PGA contours in the study area are presented on Figure 6. A summary of potential ground shaking levels for each segment is presented in Table 6, and is provided for the corridor segments on a 1/10th mile basis in the Impact Assessment Table in Appendix A.

In order to evaluate the level of ground shaking that might be anticipated at the proposed new Haskell Canyon Switching Station and expanded Barren Ridge Switching Station, site-specific analysis was performed. The 2007 California Building Code (CBC) recommends that the design of structures be based on the horizontal PGA having a 2 percent probability of exceedance in 50 years which is defined as the Maximum Considered Earthquake (MCE). The statistical return period for PGAMCE is roughly 2,475 years. The probabilistic PGAMCE for the switching stations was calculated as a percentage of gravity’s acceleration using the USGS ground motion calculator (USGS, 2008). Using the USGS ground motion calculator, the design PGA for the proposed Haskell Canyon Switching Station was 0.40g and the design PGA for the expanded Barren Ridge station was 0.52g. The potential ground shaking levels for the switching stations are also presented in Table 6. The estimates of ground motion do not include near- source factors that may be applicable to the design of structures on site. The requirements of the governing jurisdictions and the 2007 CBC should be considered in Project design.

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TABLE 6 – SUMMARY OF GROUND SHAKING POTENTIAL

APPROXIMATE GROUND SHAKING POTENTIAL1, SEGMENT (% OF THE ACCELERATION DUE TO GRAVITY) A 0.30 g B 0.25 – 0.40 g C 0.30 g D 0.30 – 0.60 g E 0.30 – 0.40 g F 0.40 – 0.60 g 115th 0.40 – 0.60 g G 0.40 – 0.80 g 2a 0.60 – 0.80 g H 0.40 – 0.60 g I 0.40 – 0.80 g J 0.40 g K 0.40 – 0.80 g Notes: 1 USGS (2002rev) data; and USGS (2008) Ground Motion Calculator (for switching stations).

Liquefaction Liquefaction is a phenomenon in which soil loses its shear strength for short periods during an earthquake. Ground shaking of sufficient duration can result in the loss of grain-to-grain contact, due to a rapid increase in pore water pressure, causing the soil to behave as a fluid for short periods. To be susceptible to liquefaction, a soil is typically cohesionless, with a grain size distribution of a specified range (generally sand and silt), loose to medium dense, below the groundwater table, and subjected to a sufficient magnitude and duration of ground shaking.

The State of California Seismic Hazards Mapping Program produces maps identifying potential liquefaction hazard zones, and has produced these maps for some quadrangles within the Project study area Many quadrangles within the study area have not been mapped by the State. Potential liquefaction hazard zones underlying proposed route segments in the study area that have been mapped by the State are shown on Figure 7. The label ―edge of data‖ on Figure 7 delineates the boundary between the quadrangles that have available data and those that do not. A summary of potential liquefaction zones is presented in Table 7, and is presented on a 1/10th mile basis in the Impact Assessment Table in Appendix A.

Review of the state maps and data indicate that portions of some segments of the Project are underlain by potential liquefaction zones. These areas are located in the southern part of the Project area and include stream, valley and canyon bottoms, typically where liquefaction-prone conditions are present (loose granular soils and shallow groundwater). Areas with potential liquefaction zones include the low-lying canyons and valleys in the ANF, southern Antelope Valley, Leona Valley, the city of Santa Clarita and the San Fernando Valley. Consequently, these mapped areas and other areas with similar geologic conditions in the study area have the potential for liquefaction to occur. The potential hazard of liquefaction is not a consideration for portions of the Project study area underlain by shallow bedrock, which is typical of the mountainous ANF and Sierra Pelona areas. The proposed Haskell Canyon and expanded Barren Ridge switching stations are not located in a liquefaction hazard zone.

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TABLE 7 – SUMMARY OF LIQUEFACTION HAZARD ZONES SEGMENT LENGTH OF SEGMENT MILES OF STATE LIQUEFACTION HAZARD ZONES (MILES) TRAVERSED1 A 13.2 None B 26.5 None C 21.7 None D 48.2 1.2 E 11.3 None F 3.6 None 115th 4.8 0.7 G 21.2 1.9 2a 6.6 None H 19.8 2.2 I 31.9 10.4 J 12.0 1.1 K 15.4 8.1 Notes: 1 Data from CGS Seismic Hazards Mapping Program. Data not available for some quadrangles in the Project study area.

Landslides Landslides typically occur in areas of steep slopes where underlying earth materials are relatively weak and particularly where high rainfall occurs and/or high groundwater levels are present. Landslides can consist of rockfalls, shallow slumps, mudflows and erosional failures, or deeper-seated rotational and block failures. Shallow failures are typically caused by high incident rainfall or concentrated surface runoff conditions that weaken surficial materials. Rotational slides, block-type slides and rockfalls form deeper within the ground, typically within rock formations, and are generally related to discontinuities in the rock that manifest into a sliding surface. Rainfall and other water infiltration into the ground can exacerbate and trigger these deeper sliding conditions. Ground shaking due to earthquakes can cause landslides to develop, trigger incipient landslides or reactivate ancient landslides.

Geologic maps produced by Thomas W. Dibblee that are available for quadrangles in the mountainous southern portion of the Project study area were reviewed for mapped landslides located within the study corridors. In addition, landslide maps contained in the State of California Seismic Hazards Reports were reviewed for mapped landslides located within the study corridors. Based on review of these referenced geologic maps of the Project study area, some existing landslides are mapped within the 500-foot-wide study corridors for the proposed segments. The State of California Seismic Hazards Mapping Program produces maps identifying potential earthquake-induced landslide hazard zones, and has produced these maps for some quadrangles within the Project study area. Many quadrangles within the study area have not been mapped by the State.

Areas of mapped landslides and earthquake-induced landslide hazard zones are predominantly located in the southern part of the Project area in the mountainous areas of the ANF and Sierra Pelona. Landslides are more likely to occur in these areas where steep slopes are present. Consequently, these mapped areas and other areas with similar steep slope conditions in the study area have potential for landslides and earthquake-induced landslides to occur. The potential for landslides and earthquake-induced landslides is not a consideration for portions of the study area with gentle to moderate topographic gradients, including much of the Antelope Valley, Mojave Desert and low-lying valley areas.

Mapped landslides are shown on the Mapped Landslide Inventory map, Figure 8. Potential earthquake- induced landslide hazard zones underlying proposed route segments in the study area that have been mapped by the State are shown on Figure 9. The label ―edge of data‖ on Figure 9 delineates the boundary between the quadrangles that have available data and those that do not. A summary of mapped landslides and earthquake-induced landslide hazard zones traversed by each segment is presented in Table 8, and is presented on a 1/10th mile basis in the Impact Assessment Table in Appendix A. Landslides are mapped

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TABLE 8 – SUMMARY OF MAPPED LANDSLIDES AND EARTHQUAKE-INDUCED LANDSLIDE HAZARD ZONES SEGMENT POTENTIAL EARTHQUAKE- LENGTH OF SEGMENT MAPPED LANDSLIDES INDUCED LANDSLIDE HAZARD (MILES) TRAVERSED (MILES)1 ZONES TRAVERSED (MILES)2 A 13.2 None None B 26.5 None None C 21.7 None None D 48.2 6.6 5.6 E 11.3 None None F 3.6 None None 115th 4.8 None 0.1 G 21.2 0.2 2.6 2a 6.6 None 0.6 H 19.8 2.0 4.8 I 31.9 4.1 18.8 J 12.0 5.5 7.0 K 15.4 2.7 9.3 Notes: 1 Data from Geologic Maps by Dibblee; and from CGS Seismic Hazards Zones Reports. Data not available for some quadrangles in the Project study area. 2 Data from CGS Seismic Hazards Mapping Program. Data not available for some quadrangles in the Project study area.

Soil Erosion Erosion refers to the process by which soil or earth material is loosened or dissolved and removed from its original location. Erosion can occur by varying processes and may occur in the Project area where bare soil (or rock) is exposed to wind or moving water (both rainfall and surface runoff). The processes of erosion are generally a function of material type, terrain steepness, rainfall or irrigation levels, surface drainage conditions, and general land uses. Review of geologic maps and soil data indicate that surface soils along the proposed segments are comprised of variable types of materials. In addition, the proposed segments follow varied topographic terrain ranging from gentle to steep gradients. In a general sense, steeper slope gradients provide a higher erosion potential, for similar soil types. Potential erosion of surface soils is exacerbated when saturated by rain or heavy irrigation.

Many surface soils along the proposed route segments are primarily comprised of sands with variable amounts of gravel, and some fine-grained silt and clay soils. Sandy soils typically have low cohesion, and have a relatively higher potential for erosion from surface runoff when exposed in cut slopes or utilized near the face of fill embankments. These types of sandy soils are present in much of the alluvial areas in the Antelope Valley/Mojave Desert area, and in many low-lying drainage areas of other parts of the Project. Surface soils with higher amounts of clay tend to be less erodible as the clay acts as a binder to hold the soil particles together. Hard rock formations, such as in the mountainous areas of the Project, tend to be less erodible due to the lithified nature of rock.

In order to evaluate the erosion potential of the soils underlying the Project alignments, data from the NRCS was evaluated. The data pertain to the potential hazard of erosion to ―off-road‖ and ―off-trail‖ areas along the proposed Project segments from ground disturbance due to Project construction. The erosion hazard ratings apply to the potential for sheet or rill erosion in areas where 50 to 75 percent of the areas have been exposed by ground disturbance, such as grading for access roads and tower sites. Potential areas of erosion for the Project have been categorized as slight, moderate, severe and very severe (USDA, 2008d), and are shown on Figure 10. A summary of the erosion potential of surface soils

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The soil erosion potential at the proposed Haskell Canyon Switching Station has been categorized as severe. The soil erosion potential at the expanded Barren Ridge has been categorized as slight.

TABLE 9 – SUMMARY OF EROSION POTENTIAL AREAS TRAVERSED BY EACH SEGMENT1 SEVERE TO VERY LENGTH OF SLIGHT EROSION MODERATE EROSION SEGMENT SEVERE EROSION SEGMENT (MILES) POTENTIAL (MILES) POTENTIAL (MILES) POTENTIAL (MILES) A 13.2 13.2 0.0 0.0 B 26.5 25.9 0.0 0.6 C 21.7 21.5 0.2 0.0 D 48.2 17.5 4.7 26.0 E 11.3 10.8 0.5 0.0 F 3.6 3.6 0.0 0.0 115th 4.8 2.9 0.2 1.7 G 21.2 4.6 1.9 14.7 2a 6.6 0.0 0.7 5.8 H 19.8 2.2 1.6 16.0 I 31.9 5.3 7.0 19.6 J 12.0 0.3 0.4 11.6 K 15.4 0.9 0.4 8.8 Notes: 1Data from USDA(2008d); Data for some portions of Segment K is not available.

Subsidence Subsidence is characterized as a sinking of the ground surface relative to surrounding areas, and can generally occur where deep alluvial soil deposits are present in valley areas such as the Antelope Valley, the city of Santa Clarita and the San Fernando Valley. Subsidence in alluvial valley areas is typically associated with groundwater withdrawal or other fluid withdrawal from the ground such as oil and natural gas. These geologic components can cause subsidence, which can result in the development of ground cracks, which could cause damage to the proposed transmission lines, including foundations, structures, pavements, and other hardscape features. Historical subsidence may have occurred in some of the valleys of the Project study area; however, the background review did not indicate that subsidence has been recently reported. No subsidence-induced ground cracks were observed crossing the proposed Project segments or switching station sites. Damage to existing transmission lines in these areas was not reported.

Soil Settlement Loose natural soils or undocumented/poorly compacted fill may be present in some areas at the site. Much of the study area is mantled by young alluvial soils, which are generally poorly consolidated, reflecting a history without substantial loading. The older alluvial deposits present in the study area are generally relatively dense or weakly cemented and are typically less compressible than the young alluvial soils. However, older alluvial deposits may include potentially collapsible layers above the groundwater table. Collapsible soils are distinguished by their potential to undergo a significant decrease in volume upon an increase in moisture content, even without an increase in external loads.

Portions of the Project study area contain existing fill soils associated with roadway construction, property and structure development, utilities, and other factors. The degree of compaction, material types, and underlying ground conditions of existing fill soils in the study area is unknown. Undocumented or poorly compacted fill may be present in these areas. In addition, the proposed route segments transition between highly variable materials ranging from loose soils to hard rock, and the potential for differential ground movement can exist at these transitions.

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Detailed references regarding the potential for settlement/collapse of soils in the Project study area are not available. The potential for soils prone to settlement or collapse would be evaluated on a site-specific basis during the design phase of the Project.

Expansive Soils Expansive soils may be present in geologic units that underlie the proposed Project segments. Expansive soils are characterized by their ability to undergo significant volume change (shrink or swell) due to variations in moisture content. Earth materials susceptible to these volumetric changes include soils and rock formations containing clays. Changes in soil moisture content can result from rainfall, irrigation, pipeline leakage, surface drainage conditions, perched groundwater, drought, or other factors. Volumetric change of expansive soil may cause excessive cracking and heaving of structures with shallow foundations, concrete slabs-on-grade, or pavements supported on these materials.

Due to the extent of the proposed Project segments, and lack of site-specific geologic references regarding the presence of expansive soils in the Project study area, USDA soil data from the NRCS was utilized to evaluate the presence of expansive soils. The NRCS data are limited to some soils that are present along the proposed Project segments, and expansive soils may be present in other areas of the Project not indicated by the NRCS data.

Linear extensibility percent is the method used by the NRCS to evaluate the shrink-swell potential of soils, and refers to the change in length of an unconfined clod as moisture content is decreased from a moist to a dry state. The volume change is reported as percent change for the whole soil. The shrink-swell (expansion) potential is low if the soil has a linear extensibility of less than 3 percent; moderate if 3 to 6 percent; high if 6 to 9 percent; and very high if more than 9 percent (USDA, 2007a). If the linear extensibility is more than 3 percent, shrinking and swelling can cause damage to buildings, roads, and other structures.

The linear extensibility data in the Project study area are limited to a few soil types. A summary of the expansive potential of surface soils along the proposed corridor segments, where available from the NRCS data, is presented in Table 10, and is presented on a 1/10th mile basis in the USDA Soil Table in Appendix B. NRCS data regarding the expansive potential of surface soils at the proposed Haskell Canyon Switching Station have not been reported. However, based on the nature of the earth units mapped at the site and observed during the reconnaissance (clay shale and sandstone units), moderately to highly expansive soils may be present at this site. USDA data regarding the expansive potential of surface soils at the expanded Barren Ridge Switching Station have not been reported. However, based on the sandy nature of the surface soils mapped at the site and observed during field reconnaissance, the expansive potential of the soils at this site is considered low.

TABLE 10 – SUMMARY OF EXPANSIVE SOIL POTENTIAL AREAS TRAVERSED BY EACH SEGMENT1

SEGMENT/MILEPOST LINEAR EXTENSIBILITY SOIL DESCRIPTION EXPANSION POTENTIAL RANGE PERCENT D (34.7 -36.5) Vertic Xerochrepts 7.5 High K (14.3 – 14.6, 15.3 – 15.4) Cropley-Urban land complex 7.5 High Notes: 1 Data from USDA(2007b, and 2008a, b, c and d).

Corrosive Soils The Project study area is located in a geologic environment that could potentially contain soil conditions that are corrosive to concrete and buried metal structures. Corrosive soil conditions may exacerbate the corrosion hazard to concrete foundations, metal pipes and other buried concrete or metal improvements that are planned for the Project. Corrosivity of soils is generally a function of soil resistivity, presence of

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 33 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION chlorides or sulfates, oxygen content, and pH. Typically, soil with low pH and high chloride/sulfate concentrations are more corrosive. High sulfate content soils are corrosive to concrete, and may limit concrete curing (and reduce its strength) or deteriorate concrete. Low pH and/or low resistivity soils could corrode buried metal structures.

In order to evaluate the erosion potential of the soils underlying the Project extents, data from the NRCS were evaluated. The NRCS data are available for only some of the soils traversed by the proposed Project, and some soils do not have reported information regarding their corrosive potential. Detailed assessment of the potential for corrosive soils in the Project study area would be evaluated on a site-specific basis during the design phase of the Project.

A summary of the corrosive potential of surface soils along the proposed corridor segments is presented in Table 11, and is presented on a 1/10th mile basis in the Impact Assessment Table in Appendix A. USDA data regarding the corrosive potential of surface soils at the proposed Haskell Canyon Switching Station have not been reported. The corrosive soil potential at the expanded Barren Ridge Switching Station has been categorized as low for concrete and moderate for steel.

TABLE 11 – SUMMARY OF CORROSIVE SOIL POTENTIAL AREAS TRAVERSED BY EACH SEGMENT1

LENGTH OF AREAS WITH LOW CORROSIVE MODERATE HIGH CORROSIVE SEGMENT SEGMENT AVAILABLE POTENTIAL CORROSIVE POTENTIAL (MILES) (MILES) DATA (MILES) (MILES) POTENTIAL (MILES) A 13.2 13.2 0.0 9.5 3.7 B 26.5 26.2 2.9 9.9 13.4 C 21.7 21.7 2.4 13.2 6.1 D 48.2 30.2 15.1 6.6 8.5 E 11.3 11.3 3.4 1.5 6.4 F 3.6 2.8 1.5 1.3 0.0 115th 4.8 4.7 1.8 2.8 0.0 G 21.2 6.5 2.6 3.6 0.3 2a 6.6 0.7 0.0 0.7 0.0 H 19.8 5.3 1.6 3.2 0.5 I 31.9 28.9 8.4 15.4 5.1 J 12.0 8.6 1.3 0.3 7.0 K 15.4 9.7 4.7 3.2 1.8 Notes: 1 Data from USDA(2007b, and 2008a, b, c and d). When multiple soils occur in a single 1/10th mile, the higher potential corrosive value is considered.

Groundwater Based on review of groundwater contour maps published in the CGS Seismic Hazard Evaluation reports, and available well data from the CDWR, groundwater is present underlying the proposed elements of the Project (CDWR, 2008). The historic high groundwater depths along the proposed segments of the Project are variable. In general, reported groundwater depths from available data in much of the Antelope Valley/Mojave Desert area are relatively deep and range from 138 to 336 feet below the ground surface. Some relatively shallow groundwater levels have been reported along the southern edge of the Antelope Valley and San Andreas Fault Rift Zone underlying Segments F, G and I. The data indicate that relatively shallow groundwater less than 50 feet deep is present in low-lying valley and other drainage areas in the southern portions of the Project study area. Segments D, G, I, J and K in this part of the Project study area are reportedly underlain by shallow groundwater. Data regarding groundwater levels at the proposed Haskell Canyon and expanded Barren Ridge switching stations are not available.

Data regarding areas of perched groundwater and perched groundwater depths are not readily available for the Project study area. Shallow perched groundwater can occur at variable locations due to seasonal

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A summary of approximate groundwater levels for the Project segments is presented in Table 12, and is listed for the corridor segments on a 1/10th mile basis in Appendix A.

TABLE 12 – SUMMARY OF GROUNDWATER LEVELS BY SEGMENT1

RANGE OF APPROXIMATE GROUNDWATER DEPTHS SEGMENT FROM AVAILABLE DATA (FEET) A No data available B 172 to 295 C 138 D 203 to 336 (Antelope Valley portion of segment) 10(milepost 34.8 to 35.0) E 204 to 224 F Less than 10 to 233 115th 167 G Less than 10 to 184 2a No data available. H No data available. I Less than 10 to 326 J 10 K 10 to 40 Notes: 1 CDWR (2008); CGS Seismic Hazards Evaluation Reports.

Inundation from Dam Failure, Seiche or Tsunami Based on review of the Safety Element chapters of the Los Angeles County (Los Angeles County, 1990) and Kern County General Plans (Kern County, 2007), portions of the Project study area could be affected by potential dam failures that could inundate the proposed Project corridors. The Los Angeles County General Plan indicates that areas susceptible to inundation from dam failure are present in the study area in the following locations in Los Angeles County: Bouquet Canyon and San Francisquito Canyon due to potential failure of the Bouquet Reservoir, which Segments D, G, H, J and K traverse. The south side of the Castaic Lake dam where Segments D and J traverse the inundation zone. The Antelope Acres area west of Lancaster due to potential failure of the Fairmont Reservoir, which Segments G and F traverse. The San Fernando area due to potential failure of the Van Norman reservoir at the south end of Segment K.

The General Plan for Kern County did not indicate areas of inundation from potential dam failure within the Kern County portion of the study area. The proposed Haskell Canyon and expanded Barren Ridge switching stations are not located in a dam failure inundation zone. A summary of potential dam inundation areas along the proposed corridor segments is presented in Table 13, and is presented on a 1/10th mile basis in the Impact Assessment Table in Appendix A.

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TABLE 13 – SUMMARY OF DAM FAILURE INUNDATION AREAS POTENTIAL DAM INUNDATION AREAS SEGMENT LENGTH OF SEGMENT (MILES) TRAVERSED (MILES)1 A 13.2 None B 26.5 None C 21.7 None D 48.2 1.5 E 11.3 None F 3.6 0.9 115th 4.8 None G 21.2 1.4 2a 6.6 H 19.8 0.3 I 31.9 0.8 J 12.0 1.5 K 15.4 1.0 Notes: 1 Data from County of Los Angeles, 1990, Kern County, 2005; Kern County, 2007.

A seiche is the seismically induced sloshing of water in a large enclosed basin, such as a lake, reservoir, or bay. Bouquet Reservoir is in close proximity to Segment H, and Castaic Lake is in close proximity to Segments D and J in the Project area. The General Plans reviewed did not indicate the potential for inundation due to seiche from these water bodies.

Tsunamis are open-sea tidal waves generated by earthquakes. Tsunami damage is typically confined to low-lying coastal areas. Water surge caused by tsunamis is measured by distance of run-up on the shore. Due to the distance of the Project area from the Pacific coast, tsunamis would not affect the Project.

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6.0 IMPACT ASSESSMENT - SEGMENTS

6.1 METHODOLOGY This preliminary geotechnical evaluation for the proposed BRRTP has included review of soil, geologic and seismic background information, field reconnaissance, and assessment of potential impacts and mitigation recommendations to provide findings regarding the proposed corridors within the Project area. The proposed segments within the Project area were evaluated in regards to potential impacts to geologic resources and potential geologic and seismic hazards associated with implementation of the Project.

Geologic resources that may be affected by construction of the BRRTP include surficial soils that may be subject to erosion, and distinctive geologic features. Potential geologic hazards affecting the proposed Project include landslides or mudflows, soil erosion, subsidence, soil settlement, expansive soils, corrosive soils, groundwater, and inundation from dam failure or seiche. Potential seismic hazards that may affect the proposed BRRTP are surface fault rupture from active faults that cross the proposed corridors; high levels of ground shaking, liquefaction, and earthquake-induced landslides.

The assessment of potential impacts was performed by a study of the proposed segments relative to known geologic conditions, features and potential hazards. The segments were plotted on geologic maps, fault maps, Seismic Hazards maps, Earthquake Fault Zones maps and other geologic references to evaluate the potential for impacts. GIS data were utilized for evaluation of soils, geologic units, fault locations, Earthquake Fault Zone locations, anticipated ground shaking levels, liquefaction and earthquake-induced landslide zones (for some parts of the study area), potential soil erosion areas, expansive soils, and corrosive soils.

The potential impacts were evaluated using a 500-foot-wide ―impact corridor.‖ Geologic resources and potential hazards within the impact corridor were analyzed. An Impact Assessment Table was created to evaluate the proposed segments on a 1/10th mile basis to develop an assessment of initial impacts. Recommendations for mitigation have been developed for Project impacts and are presented in Section 6.5. Residual Project impacts based on implementation of mitigation recommendations are discussed in Section 7, and are also presented on the Impact Assessment Table included in Appendix A.

6.2 GEOLOGIC RESOURCE SENSITIVITY The proposed Project has been evaluated with respect to its potential impacts on the geologic environment. Geologic resources that may be affected by construction of the BRRTP include surficial soils that may be subject to erosion, and distinctive geologic features. Assessment of the potential Project impacts on these features is based on the review of readily available USDA soil data and published geotechnical literature pertinent to the proposed Project, and limited field reconnaissance.

The following definitions have been provided regarding sensitivity criteria used for evaluation of geologic resources. Sensitivity is defined as a measure of probable adverse response of a resource to direct and indirect impacts associated with the construction, operation, and maintenance of Project components. Sensitivity levels for potential impacts to geologic resources are categorized as exclusion, high, moderate, or low, based upon the following general characteristics:

Exclusion: Areas where the siting of Project improvements is essentially precluded. This category includes areas where there would be unacceptable geologic impacts due to the construction or operation of a transmission line or switching station.

High Avoidance: Areas have high sensitivity due to substantial geologic impacts due to construction and operation of a transmission line or switching station. For the purposes of this study, areas designated as high sensitivity are considered least desirable and should be avoided, if possible, or mitigation implemented to reduce the adverse impacts.

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Moderate Avoidance: Areas have moderate sensitivity due to limited geologic impacts due to construction and operation of a transmission line or switching station. For the purposes of this study, areas designated as moderate sensitivity are not considered highly desirable, but may be used with mitigation of adverse impacts.

Low Avoidance or Opportunities: Areas have low sensitivity where there are no or slight geologic impacts due to construction and operation of a transmission line or switching station. For the purposes of this study, areas designated as low sensitivity are more desirable for the siting of Project components.

TABLE 14 – SENSITIVITY RATINGS FOR GEOLOGIC RESOURCES

SENSITIVITY RATING RESOURCE COMPONENT RATIONALE EXCLUSION HIGH MODERATE LOW Soils with Very Severe to High potential for significant impacts X Severe Erosion Potential from soil loss due to erosion. Moderate potential for significant Soils with Moderate Erosion X impacts from soil loss due to Potential erosion. Soils with Slight Erosion Low potential for significant impacts X Potential from soil loss due to erosion. Geologic Unit Contains High potential for impacts to Distinctive Geologic Features distinctive geologic features. (Prominent or Unique X Outcrops, Scenic Formations, San Andreas Fault Zone, White Tuff Beds) Geologic Unit May Contain Moderate potential for impacts to Distinctive Geologic Features distinctive geologic features. X (Significant Marker Beds, Scenic Formations) Geologic Unit (Alluvium or soil- Low potential for impacts to covered areas) Does Not distinctive geologic features. X Contain Distinctive Geologic Features Notes: Sensitivity criteria provided by Power Engineers.

6.3 POTENTIAL GEOLOGIC AND SEISMIC HAZARDS The impacts of potential geologic and seismic hazards that may affect the proposed BRRTP have been evaluated. Assessment of these potential impacts is based on geologic and seismic review of readily available published geotechnical literature and data pertinent to the proposed Project, and limited field reconnaissance.

Potential seismic hazards that may affect the proposed BRRTP involve surface fault rupture from active faults that cross the proposed corridors; high levels of ground shaking, liquefaction, and earthquake- induced landslides. Potential geologic hazards that may affect the proposed Project include landslides or mudflows, erosion, subsidence, soil settlement, expansive soils, corrosive soils, groundwater, and inundation from dam failure or seiche. 6.4 IMPACT LEVELS Table 15 presents the impact potential, as defined by CEQA, associated with each of the geologic conditions discussed in the following sections, and the corresponding impact level utilized in this study for impact assessment. According to Appendix G of the CEQA guidelines (CERES, 2005b), a project is considered to have a geologic impact if its implementation would result in or expose people/structures to

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TABLE 15 – IMPACT LEVELS

IMPACT LEVEL IMPACT POTENTIAL1 High Potentially significant impact. Moderate Less than significant with mitigation incorporation. Low Less than significant impact. No No impact. Note: 1Reference: CERES, 2005b, Appendix G, Environmental Checklist Form, Final Text, dated October 26

6.5 MITIGATION RECOMMENDATIONS The potential geologic and seismic impacts that may affect the BRRTP may be mitigated by employing sound engineering practice in the planning, design and construction of the new improvements proposed for the Project. This practice includes performance of the following general and specific techniques discussed below prior to the design and construction of the BRRTP.

6.5.1. Soil Loss/Soil Erosion Construction for the proposed Project is anticipated to create the potential for soil erosion during excavation, grading, and trenching activities for access roads, tower sites, pulling and tensioning sites and the construction of switching stations. However, with the implementation of prudent site practices during construction, water- and wind-related soil erosion can be limited and managed within construction site boundaries. Examples of these procedures would include surface drainage measures for erosion due to water, such as the use of erosion prevention mats or geofabrics, silt fencing, sandbags and plastic sheeting, and temporary drainage devices. Positive surface drainage should be accommodated at Project construction sites to allow surface runoff to flow away from site improvements, slope faces or areas susceptible to erosion. To mitigate wind-related erosion, wetting of soil surfaces and/or covering exposed ground areas and soil stockpiles could be considered during construction operations, as appropriate. The use of tackifiers may be considered to reduce the potential for water- and wind-related soil erosion.

Where deemed appropriate for areas of significant concern, limited access areas, or areas of very steep terrain, other practices could be considered to mitigate erosion. These practices may include avoiding these areas, or utilizing construction practices to reduce impacts. Helicopter-access could be utilized where warranted during construction in these areas to reduce ground disturbance by eliminating the need for access road construction. Using specialty foundations systems for towers, such as micropiles or hand- excavated foundations, could be considered to reduce the ground impact related to foundation construction. The need for these practices would be considered during the design phase of the Project based on Project improvement site locations. As needed, a Storm Water Pollution Prevention Plan (SWPPP) could be developed for construction sites that would include the use of Best Management Practices (BMPs). The SWPPP would also include specific statements about the required effectiveness of the BMPs, as well as plans for routine inspection and maintenance to ensure that the BMPs continue to function effectively.

During long-term operation of the transmission line improvements, soil erosion can be mitigated through prudent site design and maintenance practices. Design procedures can be performed to reduce soil erosion such as appropriate surface drainage design of roadways and tower pad areas to provide for positive surface runoff. Design would address reducing concentrated run-off conditions that could cause erosion rilling and affect the stability of Project improvements. The use of erosion control fabrics and roadway drainage devices can be designed and maintained to reduce erosion processes.

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 39 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION 6.5.2. Distinctive Geologic Features Distinctive geologic features are present in the Project study area, and the potential impacts to these features would be specifically evaluated during Project design. During the design phase, preliminary Project plans would be reviewed and the locations of proposed access roads, tower sites and pulling and tensioning sites would be field checked for impacts to distinctive geologic features.

Prominent rock features are, by nature, typically harder than the surrounding materials. They are, therefore, more difficult to excavate and present more difficulty in grading of roads, tower sites and pulling and tensioning sites. Project designers and contractors may prefer to avoid these features for ease of construction and in efforts to reduce Project costs. Measures to mitigate the impacts to distinctive geologic features include avoiding the features. Design considerations would include siting of towers, roads and pulling and tensioning sites away from the geologic feature. Design plans and site grading could be achieved to facilitate the highly sensitive landforms and surrounding gradients in efforts to reduce Project costs and thus avoid more highly distinctive geologic features.

6.5.3. Surface Rupture To assess the potential fault-rupture hazard for the proposed Project components related to active faults, evaluation may include review of geologic maps showing the locations of active faults relative to Project improvements. Where appropriate in close proximity to active faults, surface reconnaissance to map the locations of active faults and/or subsurface evaluation may be performed. Evaluation of potential fault- rupture hazard to Project improvements would be performed prior to design and construction so that, in the event a fault-rupture hazard exists, mitigation techniques can be implemented. Recommendations for mitigation of potential fault rupture hazard would typically include locating transmission system improvements away from the trace of an active fault, designing the conductor system for an acceptable amount of movement, or implementing systems to maintain safety and allow for displacement that could be repaired to make the system operational.

Surface reconnaissance to evaluate potential surface fault rupture may include checking of geologic maps and visual observation of the earth units and geomorphology in order to locate active faults relative to the alignment. Ground features that may indicate the location of active faults may be concealed by natural soils, fill soils or manmade improvements, and surface reconnaissance may not be adequate to locate active faults with potential for surface rupture. Consequently, subsurface exploration may be appropriate to evaluate fault locations and conditions. Subsurface evaluation might include the excavation and detailed logging of exploratory trenches and/or borings, geophysical studies such as high resolution seismic reflection, seismic refraction, ground penetrating radar, gravity and/or magnetic profiling or other applicable methods.

Transmission systems throughout California cross active faults. With the prevalence of active faulting in this seismically active region, the crossing of active faults is unavoidable. In this regard, mitigation of the potential surface fault rupture hazard in some areas of the segment may not involve avoiding the fault, but would involve designing the system for the anticipated displacement to reduce the damage while providing for the safety of the public.

Mitigation for potential fault-rupture hazard could include various techniques. Foundations for towers or other structures can be located away from the fault trace to avoid the fault. Locating improvements a sufficient distance from active faults would limit damage to the system as long as the fault ruptures along the identified surface and does not rupture along a new surface. Planning for the anticipated displacement by the use of additional slack in the conductor, or placing ―dead-end‖ tower structures on both sides of a fault trace may reduce damage to the system and non-operational time.

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 40 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION 6.5.4. Seismic Ground Shaking Site-specific evaluation of the potential ground-shaking hazard for the proposed Project components would be performed prior to design and construction so that appropriate structural design and mitigation techniques can be implemented. Typically, this evaluation would involve the use of geotechnical software programs utilizing site latitudinal and longitudinal coordinates and general site geologic information to evaluate the potential levels of ground shaking at specific locations. Where deemed appropriate during Project design, site-specific geotechnical evaluations to assess the subsurface characteristics of the on-site earth materials with regard to ground shaking could be performed. Subsurface data could be obtained through exploratory excavations and laboratory testing of soils.

Mitigation of the potential impacts of seismic ground shaking can be achieved through Project design. During the design phase, site-specific geotechnical evaluations would be performed to analyze the site- specific ground motion anticipated for the transmission line improvements. Site-specific evaluation of the potential ground shaking hazard would involve evaluation to develop seismic design parameters for use by the Project structural engineer. Structural elements of the transmission line system can then be designed to resist or accommodate appropriate site-specific ground motions and to conform to the current seismic design standards.

6.5.5. Liquefaction Liquefaction would typically be a potential hazard in parts of the Project area where liquefaction-prone conditions are present (loose granular soils and shallow groundwater) and include stream, valley and canyon bottoms within the study corridors. In these areas of the proposed Project, foundations for towers or other structures can be located to avoid potential liquefaction areas and mapped liquefaction zones, such as moving tower location upslope from a valley bottom.

To evaluate the potential liquefaction hazard for the proposed Project components in areas of potential liquefaction concern, subsurface evaluation could be performed. Site-specific evaluation of the potential liquefaction hazard would be performed prior to design and construction so that, in the event a liquefaction hazard exists, appropriate structural design and mitigation techniques can be implemented. Site-specific geotechnical evaluations to assess the liquefaction and dynamic settlement characteristics of the on-site soils would include drilling of exploratory borings, evaluation of groundwater depths, and laboratory testing of soils.

Mitigation for construction in liquefaction zones may include in-situ ground modification, removal of liquefiable layers and replacement with compacted fill, or support of Project improvements with piles at depths designed specifically for liquefaction. Pile foundations can be designed for liquefaction hazard by supporting the piles in dense soil or bedrock below the liquefiable zone or other appropriate methods as evaluated during the site-specific evaluation. Additional recommendations for mitigation of potential liquefaction may include densification by installation of stone columns, vibration, deep dynamic compaction, and/or compaction grouting.

6.5.6. Landslides To evaluate the potential for landslides, surficial slope failures and/or mudflows to affect the proposed Project components, evaluation may include review of geologic maps showing the locations of landslides and potential earthquake-induced landslide zones relative to these Project components. Where appropriate in close proximity to potential landslide areas, surface reconnaissance to map the locations of landslides and/or subsurface evaluation could be performed. Evaluation of the landslide and surficial slope failure hazard would be performed prior to design and construction so that, in the event the hazard exists, mitigation techniques can be implemented.

Surface reconnaissance to evaluate the potential for landslides and surficial slope failures would be performed in the design phase and may include checking of geologic maps and visual observation of the

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 41 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION conditions of slopes and site geomorphology in order to locate landslides or potential landslide areas relative to proposed tower locations and the Haskell Canyon site. Subsurface exploration may be appropriate to evaluate the potential for landslides and surficial slope failures. Subsurface evaluation might include the excavation and detailed logging of exploratory trenches, test pits and/or borings. Slope stability computer analyses may be performed to address the stability of slopes in the Project areas.

To mitigate the potential landslide hazard in some areas of the proposed Project, transmission towers can be located away from a landslide, and avoid it by spanning across, above or below the landslide feature. Access roads can be designed and constructed to avoid landslides or reduce impacts due to landslides through grading techniques. Where deemed appropriate for areas of significant concern, helicopter-based construction techniques may be implemented to avoid building access roads across landslides or landslide-prone terrain. Measures to mitigate potentially unstable slope conditions and mitigate the potential for landslides and surficial slope failures include: excavating potentially unstable material resulting in a flatter more stable slope configuration; reduction of landslide driving forces by removal of earth materials at the top of the landslide; construction of buttress and/or stabilization fills; construction of retaining walls, installation of rock bolts on the face of the slope, or installation of protective wire mesh on the slope face; and/or the construction of debris impact walls at the toe of the slope to contain rock fall debris.

6.5.7. Subsidence The background review did not indicate that subsidence has been recently reported in the Project area. Therefore, potential subsidence is considered to have a low impact and recommendations for mitigation are not provided.

6.5.8. Soil Settlement To evaluate the potential for settlement to affect the proposed Project components, surface reconnaissance and subsurface evaluation could be performed. During the design phase of the Project, site-specific geotechnical evaluations would be performed to assess the settlement potential of the on-site natural soils and undocumented fill. This may include detailed surface reconnaissance to evaluate site conditions, and drilling of exploratory borings and laboratory testing of soils, where warranted, to evaluate site conditions. Evaluation of the potential soil settlement hazard would be performed prior to design and construction so that, in the event the hazard exists, mitigation techniques can be implemented.

In some areas of the proposed Project, foundations for towers or other structures and roadways can be located to avoid potential areas of settlement. Examples of possible mitigation for soils with potential for settlement include removal of the compressible/collapsible soil layers and replacement with compacted fill; surcharging to induce settlement prior to construction of improvements; allowing for a settlement period after or during construction of new fills; and specialized foundation design including the use of deep foundation systems to support structures. Varieties of in-situ soil improvement techniques are also available, such as dynamic compaction (heavy tamping) or compaction grouting.

6.5.9. Expansive Soils To evaluate the potential for expansive soils to affect the proposed Project components, subsurface evaluation including laboratory testing could be performed. Site-specific, subsurface evaluation could be conducted during the design phase of the Project to evaluate the potential extent of expansive soils along the proposed segments. Where expansive soil conditions are found to occur and are considered detrimental to proposed improvements, mitigation techniques can be implemented. Evaluation of the potential expansive soils hazard would be performed prior to design and construction so that, in the event the hazard exists, mitigation techniques can be implemented, including avoiding areas of expansive soils. To avoid site-specific subsurface evaluation, design measures to accommodate expansive soil activity can be included in the initial design for the proposed Project improvements.

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 42 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION Mitigation for expansive soils would typically include techniques such as overexcavation and replacement with non-expansive soil, chemical treatment (e.g., lime or cement), moisture control, and/or specific structural design for expansive soil conditions developed during design of the Project.

6.5.10. Corrosive Soils To evaluate the potential for corrosive soils to affect the proposed Project components, subsurface evaluation including laboratory testing could be performed. Evaluation of the corrosive soil potential can be accomplished by testing and analysis of soils at foundation design depths. The laboratory tests conducted on the soils prior to construction and improvement plan preparation would include corrosivity tests to evaluate the corrosivity of the subsurface soils. Review of these data by a corrosion engineer would result in corrosion protection measures suitable to the Project elements. Evaluation of the potential corrosive soils hazard would be performed prior to design and construction so that, in the event the hazard exists, mitigation techniques can be implemented, including avoiding areas of corrosive soils. To avoid site-specific subsurface evaluation, corrosion protection measures can be included in the initial design for the proposed Project improvements.

Mitigation of corrosive soil conditions may involve the use of concrete resistant to sulfate exposure. Corrosion protection for metals may be needed for underground foundations or structures in areas where corrosive groundwater or soil could potentially cause deterioration. Typical mitigation techniques include epoxy and metallic protective coatings, the use of alternative (corrosion resistant) materials, and selection of the appropriate type of cement and water/cement ratio. Specific measures to mitigate the potential effects of corrosive soils would be developed in the design phase.

6.5.11. Groundwater To evaluate the potential for groundwater that may affect construction of the proposed Project components, subsurface evaluation could be performed. Evaluation of the potential shallow groundwater hazard would be performed prior to design and construction so that, in the event the hazard exists, mitigation techniques can be implemented, including avoiding areas of shallow groundwater or preparation for the anticipated groundwater during construction. Site-specific geotechnical evaluations to assess the groundwater characteristics may include review of available groundwater data, drilling of exploratory borings, evaluation of groundwater depths, and possible installation of groundwater monitoring wells, where needed.

Measures to mitigate potential shallow groundwater conditions would include: shoring/casing of excavations below the groundwater table to prevent inundation of the excavated area; pumping groundwater from excavations to keep levels below a specified depth; using dewatering wells to pump groundwater out of the ground and lower the groundwater table at specified locations; and, where needed, utilizing more advanced, and costly techniques to manage groundwater, such as the use of subsurface grout curtains or soil/cement walls. Measures to mitigate the potential impacts of excavation spoils that are saturated due to groundwater would include sandbags or berms, or the use of bins or drums to contain the excavation materials and water and reduce impacts to surface soils and surface water quality. Where deemed appropriate for areas of significant concern, the use of micropile foundations for towers could be utilized to reduce construction impacts related to drilling of larger excavations for foundations, which may be prone to impacts due to shallow groundwater.

6.5.12. Inundation from Dam Failure, Seiche or Tsunami To evaluate the potential for dam inundation or seiche to affect the proposed Project components, review of dam inundation maps and detailed hydrologic evaluation could be performed to assess the risks and potential effects of inundation to particular Project areas. Evaluation of potential dam inundation or seiche hazards at site-specific locations would be performed prior to design and construction so that, in the event of inundation, measures could be in place to mitigate the effects.

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 43 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION Measures to mitigate the potential inundation due to dam failure or seiche would include raising the elevation of the proposed transmission tower locations to keep them elevated above the potential inundation level. These types of inundation effects are anticipated to be temporary, and may necessitate minor maintenance in the affected segments to make the system operational.

Since the Project area is not considered susceptible to tsunami inundation, the proposed Project would not result in impacts related to tsunamis, and recommendations for mitigation are not provided.

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 44 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION

7.0 IMPACT RESULTS

The initial impact results for each component of the Project are presented in the following sections. These Project components include: 1) construction of the new 230 kV transmission line from Barren Ridge to Haskell Canyon; 2) the new 230 kV circuit placed on existing towers from Haskell Canyon to Castaic; 3) the 230 kV reconductoring placed on existing towers from Barren Ridge to Rinaldi; 4) construction of the new Haskell Canyon Switching Station; and 5) expansion of the Barren Ridge Switching Station.

Assessment of the results for the proposed new 230 kV transmission line is presented by impact type in the following sections. Summary tables are provided in the impact type sections in order to compare the level of impact of the proposed routing segments with each other. Since the components are evaluated as segments, assessment of the impacts of the new 230 kV circuit from Haskell Canyon to Castaic (evaluated as Segment J) and the 230 kV reconductoring from Barren Ridge to Rinaldi (evaluated as Segments A, B, G and K) is also presented in Section 7.1.

7.1 NEW 230 KV TRANSMISSION LINE - SEGMENTS The initial impact results in this section of the report are presented in order to evaluate the proposed construction of the new 230kv transmission line. A summary of the relative geologic impacts for each proposed segment of the transmission line Project is summarized below in Table 16. Detailed discussion and presentation of the individual impacts follows.

This preliminary geotechnical evaluation has considered assessment of the potential geologic resources in the affected environment that may be impacted by construction of the proposed BRRTP. Inversely, the preliminary evaluation has also considered the potential geologic and seismic hazards in the affected environment that may have impacts on development of the proposed Project. The potential geologic resources in the environment that may be impacted by the Project include highly erosion-sensitive soils and distinctive geologic features. The potential geologic and seismic hazards that may have an impact to the Project include surface fault rupture, seismic ground shaking, liquefaction, landslides, erosion, settlement, expansive soils, corrosive soils, groundwater and inundation from potential dam failure. These potential impacts may affect individual components of the Project, including transmission towers, access roads and/or the switching stations.

During the design phase when the Project components are being sited, the potential Project impacts would be evaluated through data review, geologic reconnaissance and subsurface exploration, as appropriate. The results of the site-specific evaluations would be incorporated into the design of the Project components. Through this process, the highly sensitive geologic resources that could be affected would be located and mitigation would be implemented to reduce the impacts to low levels. The potential geologic and seismic hazards would be considered relative to the construction of Project components, and mitigation techniques would be developed to reduce the impacts to low levels that would be appropriate for design. With the implementation of the appropriate mitigations, the initial impacts to geologic resources and impacts related to potential seismic and geologic hazards can be reduced to low residual levels.

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 45 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION

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TABLE 16 – RELATIVE GEOLOGIC IMPACTS

Potential Geologic Impact Inundation Segment Distinctive Surface Ground Lique- Land- Soil Subsidence/ Expansive Corrosive Ground- from Dam Corridor Soils1 Geologic Fault Shaking4 faction5 slides6 Erosion 7 Settlement 8 Soils9 Soils10 water11 Failure or Features2 Rupture3 Seiche 12 A 1 1 3 2 1 1 1 1 1 2 - 1 B 3 1 2 2 1 1 3 1 1 3 1 1 C 2 1 1 2 1 1 2 1 1 3 1 1 D 3 2 3 3 2 2 3 1 2 3 3 2 E 2 2 1 2 1 1 2 1 1 3 1 1 F 1 1 1 3 1 1 1 1 1 2 3 2 115th 3 2 1 3 2 1 3 1 1 2 1 1 G 3 2 3 3 2 2 3 1 1 3 3 2 2a 3 2 2 3 1 2 3 1 1 2 - 1 H 3 2 3 3 2 2 3 1 1 3 - 2 I 3 3 3 3 2 2 3 1 1 3 3 2 J 3 2 1 2 2 2 3 1 1 3 3 2 K 3 2 3 3 2 2 3 1 2 3 3 2 NOTES: 1 Rating 1 = Route traverses soils with low sensitivity rating. 7 Rating 1 = Route traverses areas of slight erosion potential. Rating 2 = Route traverses soils with moderate sensitivity rating. Rating 2 = Route traverses areas of moderate erosion potential. Rating 3 = Route traverses soils with high sensitivity rating. Rating 3 = Route traverses areas of severe to very severe erosion potential.

2 Rating 1 = Route traverses distinctive geologic features with low sensitivity rating. 8 Rating 1 = Route traverses areas with no reported compressible/collapsible soils or subsidence. Rating 2 = Route traverses distinctive geologic features with moderate sensitivity rating. Rating 2 = Route traverses areas of reported compressible/collapsible soils or subsidence. Rating 3 = Route traverses distinctive geologic features with high sensitivity rating. 9 Rating 1 = Route traverses areas with no reported expansive soils. 3 Rating 1 = Route does not traverse a known active or potentially active fault. Rating 2 = Route traverses areas with reported potential for expansive soils. Rating 2 = Route traverses a potentially active fault. Rating 3 = Route traverses an active fault or is located in an Earthquake Fault Zone. 10 Rating 1 = Route traverses areas of reported soils with low corrosive potential. Rating 2 = Route traverses areas of reported soils with moderate corrosive potential. 4 Rating 1 = Route traverses areas with estimated Peak Horizontal Ground Acceleration (PGA) less than 0.3g. Rating 3 = Route traverses areas of reported soils with high corrosive potential. Rating 2 = Route traverses areas with estimated PGA in the range of 0.3g to less than 0.6g. Rating 3 = Route traverses areas with estimated PGA in the range of 0.6g to 0.8g. 11 Rating 1 = Route traverses areas of reported groundwater more than 50 feet deep. Rating 2 = Route traverses areas of reported groundwater between 25 and 50 feet deep. 5 Rating 1 = Route does not traverse a Liquefaction Hazard Zone. Rating 3 = Route traverses areas of reported groundwater less than 25 feet deep. Rating 2 = Route traverses a Liquefaction Hazard Zone. 12 Rating 1 = Route traverses areas with no reported potential for inundation from dam failure or seiche. 6 Rating 1 = Route does not traverse an Earthquake-Induced Landslide Hazard Zone or mapped landslide. Rating 2 = Route traverses areas with potential for inundation from dam failure or seiche. Rating 2 = Route traverses an Earthquake-Induced Landslide Hazard Zone or mapped landslide. - Areas with no data available.

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 47 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION

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ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 48 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION 7.1.1. Soils This potential geologic impact refers to the proposed Project’s potential to cause erosion loss of surface soils, and impacts to potentially sensitive soils. Based on NRCS soil data, soils with varying degrees of erosion potential are located along the proposed Project segments and at the switching station sites. Potential areas of erosion for the Project have been categorized as slight, moderate, severe and very severe (USDA, 2008d). These erosion potential levels correspond to low, moderate and high sensitivity ratings, respectively. If implementation of the proposed Project components would cause significant erosion and loss of high-sensitivity-rating surface soils, then erosion would have a high impact on soil resources. Significant erosion and loss of moderate-sensitivity-rating surface soils would have a moderate impact on the soil resources. Significant erosion and loss of low-sensitivity-rating surface soils would have a low impact on the soil resources.

A summary of sensitivity levels/potential initial impacts to soils is provided below in Table 17. A summary of sensitivity ratings for soils underlying the proposed Project segments is presented on a 1/10th mile basis in the USDA Soils table in Appendix B.

Future construction activities for the Project would result in ground surface disruption during excavation, grading, and trenching that would create the potential for erosion to occur and impact sensitive soils. However, the erosion potential during construction can be mitigated with prudent site management practices during construction (specified in the SWPPP). Following development of site improvements, erosion can be mitigated by long-term erosion management practices incorporated into the design and maintenance of the Project. With incorporation of mitigation techniques, future site erosion and impacts to sensitive soils can be reduced. Potential soil erosion related to the Project development is considered to have a low residual impact with mitigation incorporation.

TABLE 17 – SUMMARY OF POTENTIAL INITIAL IMPACTS TO SOILS1 SEGMENT MODERATE LENGTH OF LOW SENSITIVITY/LOW SENSITIVITY/ HIGH SENSITIVITY/HIGH SEGMENT IMPACT LEVEL AREAS MODERATE IMPACT IMPACT LEVEL AREAS (MILES) TRAVERSED (MILES) LEVEL AREAS TRAVERSED (MILES) TRAVERSED (MILES) A 13.2 13.2 0.0 0.0 B 26.5 25.9 0.0 0.6 C 21.7 21.5 0.2 0.0 D 48.2 17.5 4.7 26.0 E 11.3 10.8 0.5 0.0 F 3.6 3.6 0.0 0.0 115th 4.8 2.9 0.2 1.7 G 21.2 4.6 1.9 14.7 2a 6.6 0.0 0.7 5.8 H 19.8 2.2 1.6 16.0 I 31.9 5.3 7.0 19.6 J 12.0 0.3 0.4 11.6 K 15.4 0.9 0.4 8.8 Notes: 1 Data from USDA(2008d); Data for some portions of Segment K are not available.

7.1.2. Distinctive Geologic Features This potential geologic impact refers to the proposed Project’s potential to cover or modify distinctive, prominent geologic features with potentially high sensitivity rating, which could occur during grading or excavation activities related to Project construction. Distinctive geologic features can include unique marker beds, scenic rock formations or significant outcrops. Based on background review and limited

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 49 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION field reconnaissance, there are distinctive geologic features that are present in some of the rock formations in the Project study area.

Geologic features traversed by the proposed segments in the BRRTP study area that are considered distinctive, and would have a high sensitivity rating, include the white tuff (volcanic ash) marker beds that are mapped and outcrop in the Bouquet Canyon/Vasquez Canyon area traversed by Segment I.

Rock formations in the Project study area are present in the southern part of Segment D, and in Segments G, 2a, H, I, J, and portions of Segment K. The majority of these geologic formations contains more common rock outcrops, exposed road cuts and soil-covered areas, and is not considered highly distinctive. However, distinctive geologic features may be present in limited areas of some rock formations in the Project study area not indicated on geologic maps or observed during field reconnaissance. Therefore, these rock formation units have been assigned a moderate sensitivity rating.

The Mojave Desert and Antelope Valley portions of the Project, and other low-lying valley areas with alluvium and soil cover, do not comprise rock formations at the ground surface and do not contain distinctive geologic features. These areas have been assigned a low sensitivity rating.

A summary of sensitivity ratings and potential initial impact levels due to distinctive geologic features is provided below in Table 18, and is presented on a 1/10th mile basis in the Impact Assessment Table in Appendix A.

The construction of the transmission Project would result in grading and excavation activities for tower and access road construction in areas of rock formations. Grading of rock formations can often be difficult, and designers and contractors typically prefer to avoid this more costly operation. Design plans and site grading could be achieved to facilitate the landforms and surrounding gradients as much as possible in efforts to reduce Project costs and thus avoid more distinctive geologic features. Therefore, the impacts related to the alteration or modification of distinctive geologic features would be reduced. Assessment of the potential for impacts to distinctive geologic features would be evaluated during the design phase of the Project when plans are being developed, and mitigation techniques would be developed, as appropriate, to reduce the impacts to distinctive geologic features to low levels. Therefore, the potential residual impacts due to distinctive geologic features are considered low with anticipated mitigation.

TABLE 18 – SUMMARY OF POTENTIAL INITIAL IMPACTS TO DISTINCTIVE GEOLOGIC FEATURES1 SEGMENT LOW IMPACT LEVEL MODERATE IMPACT HIGH IMPACT LEVEL LENGTH OF AREAS TRAVERSED LEVEL AREAS AREAS TRAVERSED SEGMENT (MILES) (MILES) TRAVERSED (MILES) (MILES) A 13.2 13.2 0.0 0.0 B 26.5 26.5 0.0 0.0 C 21.7 21.7 0.0 0.0 D 48.2 17.0 31.2 0.0 E 11.3 10.4 0.9 0.0 F 3.6 3.6 0.0 0.0 115th 4.8 3.7 1.1 0.0 G 21.2 4.5 16.7 0.0 2a 6.6 0.1 6.4 0.0 H 19.8 2.8 17.0 0.0 I 31.9 6.3 23.7 0.4 J 12.0 0.3 11.7 0.0 K 15.4 2.2 13.2 0.0 Notes: 1 Dibblee, 1997c, 1997f, 2002b; field observations.

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 50 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION 7.1.3. Surface Rupture The high probability for surface fault rupture within the Project study area is along active faults, particularly along the active faults designated as Earthquake Fault Zones. There is a high impact associated with construction of Project improvements across the traces of active faults and areas within the Earthquake Fault Zones. Other potentially active and inactive faults are located in the study area and underlie some of the proposed segments. Due to the less active nature of these types of faults, they have been assigned a moderate impact to the Project. A summary of potential initial impact levels due to faults crossed by the proposed Project segments is presented on a 1/10th mile basis in the Impact Assessment Table in Appendix A. A summary of potential initial impact levels due to earthquake fault zones is provided below in Table 19, and is presented on a 1/10th mile basis in the Impact Assessment Table in Appendix A.

Development within Earthquake Fault Zones would need further evaluation to address the potential for fault rupture. The initial impacts related to surface fault rupture are high. Damage could occur to the proposed transmission line improvements due to fault rupture if those elements are constructed across the fault rupture surface. Damages may include offset/damage to towers or roadways at portions of the segments crossing the fault rupture; damage to structural elements of the transmission towers that are placed across the fault rupture; or damage to facilities built across the fault rupture. Assessment of the surface fault rupture potential would be evaluated prior to design and construction of Project improvements and incorporated into the design, as appropriate, to reduce the impacts related to surface rupture to low levels. Therefore, the potential residual impacts due to surface fault rupture are considered to be low with incorporation of mitigation techniques such as fault trenching to check for fault traces and re-locating towers to avoid fault traces, as appropriate.

TABLE 19 – SUMMARY OF POTENTIAL INITIAL IMPACTS DUE TO EARTHQUAKE FAULT ZONES SEGMENT HIGH IMPACT LEVEL EARTHQUAKE FAULT LENGTH OF SEGMENT (MILES) ZONES TRAVERSED (MILES)1 A 13.2 1.4 B 26.5 None C 21.7 None D 48.2 1.5 E 11.3 None F 3.6 None 115th 4.8 None G 21.2 0.9 2a 6.6 None H 19.8 0.8 I 31.9 1.5 J 12.0 None K 15.4 2.4 Notes: 1 Hart and Bryant, 1997 (formerly Alquist-Priolo Special Studies Zones).

7.1.4. Seismic Ground Shaking The seismic hazard likely to impact the Project area is ground shaking during an earthquake on one of the nearby or distant active faults. The level of ground shaking at a given location depends on many factors, including the size and type of earthquake, distance from the earthquake, and subsurface geologic conditions. The size and type of construction also affects how particular structures perform during ground shaking. Ground shaking could cause detrimental damage to Project improvements if the appropriate design for the anticipated level of shaking is not considered. Damages due to ground shaking could include misaligned towers and other structural elements, and cracks in concrete foundations, walls and structures such as the proposed Haskell Canyon Switching Station.

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 51 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION Based on the review of seismic data, peak horizontal ground accelerations in the range of 0.25 g to 0.80 g are anticipated to affect the Project study area. Peak horizontal ground accelerations less than 0.30 g are considered to have a low initial impact; peak horizontal ground accelerations in the range of 0.30g to 0.40g are considered to have a moderate initial impact; and peak horizontal ground accelerations in the range of 0.50g to 0.80g are considered to have a high initial impact. A summary of potential initial impact levels due to ground shaking is provided below in Table 20, and is presented on a 1/10th mile basis in the Impact Assessment Table in Appendix A.

Assessment of the ground shaking potential would be evaluated prior to design and construction of Project improvements and incorporated into the design, as appropriate, to reduce the impacts related to seismic ground shaking to low levels. Therefore, the potential residual impacts due to ground shaking are considered to be low with incorporation of mitigation techniques such as designing the structural elements of the transmission line system to resist or accommodate appropriate site-specific ground motions.

TABLE 20 – SUMMARY OF POTENTIAL INITIAL IMPACTS DUE TO GROUND SHAKING

APPROXIMATE LOW MODERATE HIGH GROUND SHAKING LENGTH OF IMPACT IMPACT IMPACT SEG- POTENTIAL1 IMPACT LEVEL SEGMENT LEVEL LEVEL LEVEL MENT (% OF THE RANGE (MILES) TRAVERSED TRAVERSED TRAVERSED ACCELERATION (MILES) (MILES) (MILES) DUE TO GRAVITY, g) A 0.30 Moderate 13.2 0.0 13.2 0.0 B 0.25 – 0.40 Low to Moderate 26.5 2.7 23.8 0.0 C 0.30 Moderate 21.7 0.0 21.7 0.0 D 0.30 – 0.60 Moderate to High 48.2 0.0 34.8 13.4 E 0.30 – 0.40 Moderate 11.3 0.0 11.3 0.0 F 0.40 – 0.60 Moderate to High 3.6 0.0 3.1 0.5 115th 0.40 – 0.60 Moderate to High 4.8 0.0 1.4 3.4 G 0.40 – 0.80 Moderate to High 21.2 0.0 11.2 10.0 2a 0.60 – 0.80 High 6.6 0.0 0.0 6.5 H 0.40 – 0.60 Moderate to High 19.8 0.0 9.2 10.5 I 0.40 – 0.80 Moderate to High 31.9 0.0 15.8 16.1 J 0.40 Moderate 12.0 0.0 12.0 0.0 K 0.40 – 0.80 Moderate to High 15.4 0.0 2.7 12.7 Notes: 1 USGS (2002rev) data

7.1.5. Liquefaction Review of the state maps and data indicate that portions of some segments of the Project are underlain by potential liquefaction zones. Liquefaction could cause damage to proposed Project improvements without appropriate consideration during design, and areas that are mapped as liquefaction zones have a potentially high impact on the Project. The potential damaging effects of liquefaction include differential settlement, loss of ground support for foundations, ground cracking, heaving and cracking of slabs due to sand boiling, buckling of deep foundations due to liquefaction-induced ground settlement, and lateral spreading along embankments and natural slopes along drainages. A summary of potential initial impact levels due to liquefaction hazard zones is provided below in Table 21, and is presented on a 1/10th mile basis in the Impact Assessment Table in Appendix A.

The State of California Seismic Hazards Mapping Program produces maps identifying potential liquefaction hazard zones, and has produced these maps for some quadrangles within the Project study area. Many quadrangles within the study area have not been mapped by the State. Potential liquefaction hazard zones underlying proposed route segments in the study area that have been mapped by the State are included in the evaluation, where available. In order to make a comparison of the proposed route

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 52 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION segments for areas of available data and areas that do not have available data, a ratio of the miles of liquefaction zones to the miles of available data for each segment is presented below in Table 21.

According to Seismic Hazards Zones Maps published by the State of California, portions of the Project are mapped within areas that are considered susceptible to liquefaction. In addition, areas of the Project not mapped in a Seismic Hazards Zone may have potential for liquefaction. Assessment of the liquefaction potential would be evaluated prior to design and construction of Project improvements and incorporated into the design, as appropriate, to reduce the impacts related to liquefaction to low levels. Therefore, the potential residual impacts due to liquefaction are considered to be low with incorporation of mitigation techniques such as avoiding the liquefaction zone by moving tower locations upslope from valley bottoms, in-situ ground modification, or supporting towers with piles at depths designed specifically for liquefaction.

TABLE 21 – SUMMARY OF POTENTIAL INITIAL IMPACTS DUE TO LIQUEFACTION HAZARD ZONES

HIGH IMPACT LEVEL RATIO OF LENGTH OF AVAILABLE DATA LIQUEFACTION HAZARD LIQUEFACTION SEGMENT SEGMENT (MILES) (MILES) ZONES TRAVERSED ZONES TO (MILES)1 AVAILABLE DATA A 13.2 0.0 None 0.0% B 26.5 6.2 None 0.0% C 21.7 0.0 None 0.0% D 48.2 8.8 1.2 13.6% E 11.3 3.6 None 0.0% F 3.6 3.6 None 0.0% 115th 4.8 4.8 0.7 14.6% G 21.2 10.0 1.9 19.0% 2a 6.6 5.2 None 0.0% H 19.8 11.2 2.2 19.6% I 31.9 31.9 10.4 32.6% J 12.0 7.3 1.1 15.1% K 15.4 15.4 8.1 52.6% Notes: 1 Data from California Geological Survey Seismic Hazards Mapping Program for available quadrangles in the study area (some quadrangles and data not available).

7.1.6. Landslides The review of referenced geologic maps and field reconnaissance indicates that existing mapped landslides are present along some proposed segments of the Project. Additionally, some steep areas of the Project have been designated as potential Earthquake-Induced Landslide Hazard Zones by the State of California. Some mapped landslides and potential earthquake-induced landslide zones occur at the same location within the Project study corridors. Both the mapped landslide areas and potential Earthquake- Induced Landslide Hazard Zones are considered to have a potentially high initial impact on the Project, if improvements are constructed on the landslide areas. A summary of potential initial impact levels due to mapped landslides is provided below in Table 22, and is presented on a 1/10th mile basis in the Impact Assessment Table in Appendix A. A summary of potential initial impact levels due to earthquake-induced landslide hazard zones is provided below in Table 23, and is presented on a 1/10th mile basis in the Impact Assessment Table in Appendix A.

Geologic maps utilized to evaluate existing landslides in the Project study area were available for the steep mountainous areas within the ANF and surrounding mountainous areas where landslides may occur, generally along Segments D, G, 2a, H and I. In order to make a comparison of the proposed route segments, a ratio of the miles of mapped landslides to the miles of available data for each segment is included in Table 22. The State of California Seismic Hazards Mapping Program produces maps

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 53 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION identifying potential earthquake-induced landslide hazard zones, and has produced these maps for some quadrangles within the Project study area. Many quadrangles within the study area have not been mapped by the State. Potential earthquake-induced landslide hazard zones underlying proposed route segments in the study area that have been mapped by the State are included in the evaluation, where available. In order to make a comparison of the proposed route segments for areas of available data and areas that do not have available data, a ratio of the miles of earthquake-induced landslide zones to the miles of available data for each segment is included in Table 23.

Portions of the Project located in areas of steep terrain (including mapped landslide areas and areas that do not have mapped landslides) may have potential landslide hazard. Slope areas within the study area, including constructed cut slopes, fill slopes, and natural slopes, could potentially be affected by landsliding or other steep slope problems. Slopes may have potential for surficial slope failures and/or mudflows during rainfall. Slopes cut in bedrock may be subject to rock fall, rock slides, or other rock slope failures where discontinuities, such as joints and fractures, or weathered rock are encountered. Landslides and surficial slope failures (mudflows), if not mitigated, can cause damage to slopes, embankments, roadways, transmission towers, foundations and other structures that are founded on or affected by the landslide. Due to the relatively flat-lying nature of some segments of the Project in the Antelope Valley, Mojave Desert, and valleys, landslide hazards are considered low in those areas of gentle slopes.

Assessment of the landslide and mudflow potential in areas of Project improvements would be evaluated prior to design and construction improvements and incorporated into the design, as appropriate, to reduce the impacts related to landslides to low levels. Therefore, the potential residual impacts due to landslides are considered to be low with incorporation of mitigation techniques such as avoiding landslides by moving tower locations, excavating potentially unstable earth materials, slope stabilization methods, or building of retaining structures.

TABLE 22 – SUMMARY OF POTENTIAL INITIAL IMPACTS DUE TO MAPPED LANDSLIDES SEGMENT HIGH IMPACT LEVEL LENGTH OF RATIO OF MAPPED AVAILABLE DATA MAPPED LANDSLIDE SEGMENT LANDSLIDE AREAS TO (MILES)1 AREAS TRAVERSED (MILES) AVAILABLE DATA (MILES)1 A 13.2 0.0 None 0.0% B 26.5 6.2 None 0.0% C 21.7 0.0 None 0.0% D 48.2 26.0 6.6 25.4% E 11.3 3.6 None 0.0% F 3.6 3.6 None 0.0% 115th 4.8 4.8 None 0.0% G 21.2 21.2 0.2 0.9% 2a 6.6 6.5 None 0.0% H 19.8 19.8 2.0 10.1% I 31.9 31.9 4.1 12.9% J 12.0 12.0 5.5 44.7% K 15.4 15.4 2.7 17.5% Notes: 1 Data from available geologic maps by Dibblee; and from CGS Seismic Hazards Zones Reports for available quadrangles in the study area (some quadrangles and data not available).

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 54 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION

TABLE 23 – SUMMARY OF POTENTIAL INITIAL IMPACTS DUE TO EARTHQUAKE-INDUCED LANDSLIDE HAZARD ZONES

RATIO OF HIGH IMPACT LEVEL LENGTH OF EARTHQUAKE- AVAILABLE DATA EARTHQUAKE-INDUCED SEGMENT SEGMENT INDUCED LANDSLIDE (MILES)1 LANDSLIDE AREAS (MILES) AREAS TO AVAILABLE TRAVERSED (MILES)1 DATA A 13.2 0.0 None 0.0% B 26.5 6.2 None 0.0% C 21.7 0.0 None 0.0% D 48.2 8.8 5.6 63.6% E 11.3 3.6 None 0.0% F 3.6 3.6 None 0.0% 115th 4.8 4.8 0.1 2.1% G 21.2 10.0 2.6 26.0% 2a 6.6 5.2 0.6 11.5% H 19.8 11.2 4.8 42.9% I 31.9 31.9 18.8 58.9% J 12.0 7.0 7.0 100.0% K 15.4 15.4 9.3 60.4% Notes: 1 Data from CGS Seismic Hazards Zones Reports for available quadrangles in the study area (some quadrangles and data not available).

7.1.7. Soil Erosion Based on NRCS soil data, surface soils with erosion potential ranging from slight to moderate to severe and very severe have been mapped in the Project study area. In addition to the loss of surface soils as a geologic resource, erosion of soils and earth materials can cause damage to Project improvements such as tower foundations, switching station facilities, access roads, and manufactured slopes. Erosion can potentially result in the loss of support or undermining of these Project improvements. Construction of Project improvements on soils with a severe to very severe erosion potential would have a high initial impact to Project improvements. Soils with a moderate erosion potential would have a moderate initial impact, and soils with a slight erosion potential would have a low initial impact. A summary of potential initial impact levels due to soil erosion is provided below in Table 24, and is presented on a 1/10th mile basis in the Impact Assessment Table in Appendix A. The soil erosion potential at the proposed Haskell Canyon Switching Station has been categorized as severe, and the impact of erosion at this site is considered high. The soil erosion potential at the expanded Barren Ridge Switching Station has been categorized as slight, and the impact at this site is considered low.

Future construction activities for the Project would result in ground surface disruption during excavation, grading, and trenching that would create the potential for erosion to occur. However, the erosion potential during construction can be mitigated with prudent site management practices during construction. Following development of site improvements, erosion can be mitigated by long-term erosion management practices incorporated into the design and maintenance of the Project. With incorporation of mitigation techniques, future site erosion can be reduced. Potential soil erosion related to the Project development is considered to have a low residual impact with mitigation incorporation.

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TABLE 24 – SUMMARY OF POTENTIAL INITIAL IMPACTS DUE TO SOIL EROSION1 LOW IMPACT LEVEL MODERATE IMPACT HIGH IMPACT LEVEL LENGTH OF SEGMENT AREAS TRAVERSED LEVEL AREAS AREAS TRAVERSED SEGMENT (MILES) (MILES) TRAVERSED (MILES) (MILES) A 13.2 13.2 0.0 0.0 B 26.5 25.9 0.0 0.6 C 21.7 21.5 0.2 0.0 D 48.2 17.5 4.7 26.0 E 11.3 10.8 0.5 0.0 F 3.6 3.6 0.0 0.0 115th 4.8 2.9 0.2 1.7 G 21.2 4.6 1.9 14.7 2a 6.6 0.0 0.7 5.8 H 19.8 2.2 1.6 16.0 I 31.9 5.3 7.0 19.6 J 12.0 0.3 0.4 11.6 K 15.4 0.9 0.4 8.8 Notes: 1 Data from USDA (2008d). Data for some portions of Segment K are not available.

7.1.8. Subsidence The background review did not indicate that subsidence has been recently reported in the Project area. No subsidence-induced ground cracks were observed crossing the proposed Project segments or switching station sites during field reconnaissance. Damage to existing transmission improvements in these areas was not reported. However, the geologic components for subsidence are present in some parts of the Project study area (valley areas), and subsidence is considered to have a potentially low initial impact.

7.1.9. Settlement Compressible natural soils and undocumented fills pose the risk of adverse settlement under static loads imposed by new embankment fills, roadway fills, tower foundations and associated structures. Differential settlement of soils can cause damage to Project improvements including concrete structures and foundations, retaining walls, associated switching stations and maintenance structures and pavements. Constructing Project improvements on soils known to have a potential for settlement would have a high initial impact to the Project.

Since the Project would involve construction of new improvements that would be loaded upon the existing soils, potential settlement and/or collapsible soils should be a consideration in design and construction of Project improvements. Assessment of the potential for soils prone to settlement would be evaluated prior to design and construction of Project improvements and mitigation techniques would be developed, as appropriate, to reduce the impacts related to settlement to low levels. Therefore, the potential residual impacts due to soil settlement are considered low with incorporation of mitigation techniques such as avoiding areas prone to settlement, removal and recompaction of compressible soils, specialized foundation design including the use of deep foundation systems to support structures, and in- situ ground modification.

7.1.10. Expansive Soils Based on limited NRCS soil data, potentially expansive soils may be present along portions of Segments D and K of the proposed Project. Expansive soils may also be present in areas of the Project not indicated by the limited NRCS soil data.

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 56 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION Expansive soils are characterized by their ability to undergo significant volume change (shrink or swell) due to variations in moisture content. Changes in soil moisture content can result from rainfall, irrigation, pipeline leakage, surface drainage, perched groundwater, drought, or other factors. Volumetric change of expansive soil may cause excessive cracking and heaving of structures with shallow foundations, concrete slabs-on-grade, or pavements supported on these materials. Constructing Project improvements on soils known to be potentially moderately to highly expansive would have a moderate to high impact to the Project. Constructing Project improvements on soils categorized with a low expansion potential would have a low impact to Project improvements. The relative potential impact of expansive soils is low for deep foundations such as deep tower foundations, since volumetric changes of expansive soils diminish with overburden depth.

Detailed assessment of the potential for expansive soils would be evaluated during the design phase of the Project and mitigation techniques would be developed, as appropriate, to reduce the impacts related to expansive soils to low levels. Therefore, the potential residual impacts due to expansive soils are considered low with incorporation of mitigation techniques such as avoiding areas of expansive soils, overexcavation and replacement with non-expansive soil, soil treatment, moisture control, and/or specific structural design for expansive soil conditions developed during design of the Project.

7.1.11. Corrosive Soils Based on NRCS soil data, potentially corrosive soils may be present along some segments of the proposed Project.

Corrosive soils, especially in areas of shallow groundwater that may be present in portions of the study area, can present a corrosion hazard to concrete in contact with soil, concrete and metal foundations, and other buried metal structures such as utility lines. Areas of corrosive soil could cause of premature deterioration of these underground structures or foundations. Constructing Project improvements on soils with a low corrosive potential would have a low initial impact to the improvements; constructing Project improvements on soils with a moderate corrosive potential would have a moderate initial impact to the improvements; and constructing improvements on soils known to be potentially highly corrosive would have a high initial impact to the Project. A summary of potential initial impact levels due to corrosive soils is provided below in Table 25, and is presented on a 1/10th mile basis in the Impact Assessment Table in Appendix A.

Assessment of the potential for corrosive soils would be evaluated during the design phase of the Project through soil testing procedures, and mitigation techniques would be developed, as appropriate, to reduce the impacts related to corrosive soils to low levels. Therefore, the potential residual impacts due to corrosive soils are considered low with incorporation of mitigation techniques such as avoiding areas of corrosive soils, the use of concrete resistant to sulfate exposure and selection of the appropriate type of cement and water/cement ratio, protective coatings for metallic substructures and components, and the use of alternative (corrosion resistant) materials.

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 57 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION

TABLE 25 – SUMMARY OF POTENTIAL INITIAL IMPACTS DUE TO CORROSIVE SOILS1 SEGMENT LENGTH OF AREAS WITH LOW IMPACT MODERATE HIGH IMPACT Segment (Miles) AVAILABLE DATA CORROSIVE SOIL IMPACT CORROSIVE (MILES) POTENTIAL (MILES) CORROSIVE SOIL SOIL POTENTIAL POTENTIAL (MILES) (MILES) A 13.2 13.2 0.0 9.5 3.7 B 26.5 26.2 2.9 9.9 13.4 C 21.7 21.7 2.4 13.2 6.1 D 48.2 30.2 15.1 6.6 8.5 E 11.3 11.3 3.4 1.5 6.4 F 3.6 2.8 1.5 1.3 0.0 115th 4.8 4.7 1.8 2.8 0.0 G 21.2 6.5 2.6 3.6 0.3 2a 6.6 0.7 0.0 0.7 0.0 H 19.8 5.3 1.6 3.2 0.5 I 31.9 28.9 8.4 15.4 5.1 J 12.0 8.6 1.3 0.3 7.0 K 15.4 9.7 4.7 3.2 1.8 Notes: 1 Data from USDA(2007b, and 2008a, b, c and d). When multiple soils occur in a single 1/10th mile, the higher potential impact corrosive value is considered.

7.1.12. Groundwater Groundwater depths underlying the Project components are variable and are reported to range from less than 10 feet deep to more than 300 feet deep. Based on the reported depths to groundwater and anticipated depth of construction activities for new foundations for Project components, groundwater may affect portions of the proposed Project. In areas where shallow groundwater is reported to be 25 feet deep or less, groundwater is considered to have a high initial impact to the Project. Groundwater ranging from 25 to 50 feet deep is considered to have a moderate initial impact; and groundwater levels deeper than 50 feet have a low initial impact to the Project. A summary of potential initial impact levels due to groundwater is provided in Table 26, and is presented on a 1/10th mile basis in the Impact Assessment Table in Appendix A.

Subsurface construction activities for Project implementation at the site are anticipated to consist of relatively shallow excavations for roadway construction and tower pads and may involve deeper excavations for foundations and other improvements. Groundwater in excavations can cause instability of the excavations, and present a constraint to the construction of foundations. Shallow groundwater less than 50 feet deep, if encountered, can have adverse effects on the construction activities for the Project.

Due to the potentially shallow groundwater levels reported along segments of the Project, wet or saturated soil conditions may be encountered in excavations during construction. In addition, areas of shallow groundwater may be encountered where not previously reported, and areas of perched groundwater may be encountered along segments of the Project. Groundwater in excavations can cause instability of the excavations, and present a constraint to the construction of foundations. Excavations for foundations extending below the groundwater table or in areas with shallow perched groundwater may need to be cased/shored and/or dewatered to maintain stability of the excavations and provide access for construction. Saturated soils encountered in excavations below the groundwater can be difficult for the contractor to handle. Groundwater from the excavation spoils brought to the surface can contribute to soil erosion and surface water quality during construction.

Shallow groundwater can also impact ground stability, and foundation design of proposed improvements, as well as the methods and costs of construction. If not adequately monitored by the contractor, dewatering of excavations could induce consolidation of the underlying soils, which could cause ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 58 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION differential settlement of existing structures and improvements located near the excavation. The amount of consolidation due to dewatering would depend on many factors, including the areal extent and depth of dewatering, soil type, soil density, and the methods used by the dewatering contractor. Excavations for the underground structures would need to be performed with care to reduce the potential for lateral deflection of excavation sidewalls and/or shoring, which could also cause differential movement of structures located near the excavation.

Groundwater levels may be influenced by seasonal variations, variations in ground surface topography, precipitation, irrigation practices, soil/rock types, groundwater pumping, and other factors and are subject to fluctuations. Shallow perched groundwater or groundwater seepage may be present in locations. Further study, including subsurface exploration, would be performed during the design phase to evaluate the presence of groundwater, seepage, and/or perched groundwater at the site and the potential impacts on design and construction of Project improvements. Assessment of the potential for shallow groundwater would be evaluated during the design phase of the Project and mitigation techniques would be developed, as appropriate, to reduce the impacts related to shallow groundwater to low levels. Therefore, the potential residual impacts due to shallow groundwater are considered low with incorporation of mitigation techniques such as construction dewatering.

TABLE 26 – SUMMARY OF POTENTIAL INITIAL IMPACTS DUE TO GROUNDWATER1

MILES OF MILES OF LOW MILES OF HIGH LENGTH OF AREAS WITH NO MODERATE IMPACT LEVEL IMPACT LEVEL SEGMENT SEGMENT AVAILABLE DATA IMPACT LEVEL TRAVERSED TRAVERSED (MILES) (MILES) TRAVERSED (MILES) (MILES) (MILES) A 13.2 0.0 0.0 0.0 0.0 B 26.5 2.6 2.6 0.0 0.0 C 21.7 0.1 0.1 0.0 0.0 D 48.2 0.5 0.3 0.0 0.2 E 11.3 0.2 0.2 0.0 0.0 F 3.6 0.5 0.2 0.0 0.3 115th 4.8 0.1 0.1 0.0 0.0 G 21.2 1.5 0.1 0.1 1.3 2a 6.6 0.0 0.0 0.0 0.0 H 19.8 1.2 0.0 0.0 1.2 I 31.9 5.2 0.1 0.0 5.1 J 12.0 0.2 0.0 0.0 0.2 K 15.4 4.5 0.1 2.2 2.2 Notes: 1 Based on available data from CDWR (2008), and CGS Seismic Hazards Evaluation Reports.

7.1.13. Inundation from Dam Failure, Seiche or Tsunami Based on the review of the County of Los Angeles General Plan Safety Element (1990), portions of the proposed Project segments are located in several potential dam failure inundation zones. Inundation due to dam failure could cause damage to Project improvements including erosion of earth materials which could undermine foundation support. The potential initial impacts due to inundation from dam failure are considered high. A summary of potential initial impact levels due to dam failure inundation is provided in Table 27, and is presented on a 1/10th mile basis in the Impact Assessment Table in Appendix A.

Dams and reservoirs in California are monitored by various governmental agencies (such as the State of California Division of Safety of Dams and the U.S. Army Corps of Engineers) to guard against the threat of dam failure or seiche. Current design and construction practices, and ongoing programs of review, modification, seismic retrofitting or total reconstruction of existing dams are intended to see that dams are capable of withstanding the maximum credible earthquake for the site. Due to the regulatory monitoring

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 59 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION of dams and reservoirs, the residual impact of inundation due to dam failure is considered a low impact to the Project.

The General Plans of Los Angeles and Kern Counties did not indicate the potential for inundation due to seiche from water bodies within the Project study area. The Project site is not within an area considered to be susceptible to tsunami inundation due to the distance from the Pacific coast. Therefore, the proposed Project would not result in, or expose people to, impacts related to tsunamis.

TABLE 27 – SUMMARY OF POTENTIAL INITIAL IMPACTS DUE TO DAM FAILURE INUNDATION

LENGTH OF SEGMENT HIGH IMPACT LEVEL INUNDATION AREAS TRAVERSED SEGMENT (MILES) (MILES)1 A 13.2 None B 26.5 None C 21.7 None D 48.2 1.5 E 11.3 None F 3.6 0.9 115th 4.8 None G 21.2 1.4 2a 6.6 None H 19.8 0.3 I 31.9 None J 12.0 1.5 K 15.4 1.0 Notes: 1 Data from County of Los Angeles, 1990; Kern County, 2005; Kern County, 2007.

7.2 NEW 230 KV CIRCUIT Between the proposed Haskell Canyon Switching Station and the existing Castaic Power Plant, LADWP proposes the addition of 12 miles of a new 230 kV transmission circuit onto existing Castaic – Olive 230 kV Transmission Line structures (towers 1-1 through 12-1).

The addition of a new circuit on existing towers would require many of the same activities of a new transmission line (surveying of ROW, rehabilitation of existing access and spur roads, clearing of ROW, conductor installation, ground rod installation, and cleanup). The work would be within existing ROW, and existing access and spur roads would be utilized. The evaluation of the proposed new 230kV circuit has been incorporated into the affected environment, impact results and impact assessment sections of this preliminary evaluation as the Segment J corridor.

7.3 RECONDUCTORING LADWP proposes the reconductoring of 76 miles of the existing BR-RIN 230 kV transmission line with larger conductors from the Barren Ridge Switching Station to Rinaldi Substation. The BR-RIN is located along Segments A, B, G, and K. From Haskell Canyon headed south to Rinaldi Substation, the BR-RIN is located on the same four-circuit structures as the Castaic-RS-J, Castaic-Sylmar, and Castaic-Olive 230 kV transmission lines.

The upgrade of the existing BR-RIN would also necessitate many of the same activities of the new transmission line (surveying of ROW, rehabilitation of existing access and spur roads, clearing of ROW, conductor installation, ground rod installation, and cleanup). The existing line would be removed and used to pull the new conductor. Some of the towers would need to be modified or replaced, and/or foundations reinforced, to carry the additional weight of the new heavier conductor. The work would remain within the existing ROW. ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 60 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION

Since the reconductoring of the BR-RIN 230 kV transmission line may involve activities similar to construction of the proposed new transmission line, the evaluation of the reconductoring of the existing transmission line is presented in the affected environment, impact results and impact assessment sections of this preliminary evaluation as Segments A, B, G and K.

7.4 NEW HASKELL CANYON SWITCHING STATION As a component of the BRRTP, LADWP proposes the construction of the new Haskell Canyon Switching Station in Haskell Canyon, south of the ANF at the convergence of several existing and proposed 230 kV transmission lines (the existing BR-RIN, the proposed double-circuit Barren Ridge-Haskell Canyon, existing Castaic-Northridge, Castaic-Sylmar, Castaic-Olive, and the proposed Castaic to Haskell Canyon). The station would be 500 feet by 600 feet to accommodate the necessary electrical equipment. Construction of the new Haskell Canyon Switching Station would consist of clearing of access roads, site grading and development, installation of electrical conduits for equipment power and control, and installation of structures and equipment. Equipment needed for station construction would include backhoes, drill rigs, concrete trucks, flatbeds and trucks. Cranes, man-lifts, portable welding units, line trucks and mechanic trucks would also be utilized.

Evaluation of the affected environment for the proposed new Haskell Canyon Switching Station is presented in the Affected Environment section of this preliminary evaluation. In summary, review of referenced soil, geologic, and seismic background data indicates that the Haskell Canyon site is underlain by Tertiary marine and non-marine sedimentary formations. The USDA soil type underlying the site is mapped as the Calciserollic Xerochrepts-Calleguas family-Modesto family, which has a high sensitivity rating based on the severe erosion potential. Distinctive geologic features were not observed at the Haskell Canyon site. The site is not crossed by a known active fault, and the potential for surface rupture is considered low. Potential seismic ground shaking at the site is on the order of 0.40g. The site is not located in a liquefaction hazard zone or earthquake-induced landslide hazard zone based on the State of California Seismic Hazards Zones map. Landslides are mapped and were observed in the vicinity of the Haskell Canyon site. There are no USDA data available regarding the potential for expansive soils or corrosive soils at the site. There are no data available regarding groundwater levels at the Haskell Canyon site. The Haskell Canyon site is not located in a dam failure inundation zone.

Assessment of the potential initial impacts for construction of the new Haskell Canyon Switching Station includes the following impact results: The soil sensitivity rating at Haskell Canyon has been categorized as high, and the initial impact of erosion of soils at this site is considered high. Highly sensitive distinctive geologic features were not observed at the Haskell Canyon site. Based on the sedimentary rock formations present at the Haskell Canyon site, the initial impact to distinctive geologic features is considered moderate. The Haskell Canyon site is not located in an Earthquake Fault Zone and the initial impacts related to surface fault rupture are considered low. The design PGA for the proposed Haskell Canyon station is 0.40g. The ground shaking potential at the station site is considered to have a moderate initial impact. The Haskell Canyon site is not located in a potential liquefaction zone based on the State of California Seismic Hazards Zones map, and the initial impacts related to liquefaction are considered low. The Haskell Canyon site is not located in a potential earthquake-induced landslide zone based on the State of California Seismic Hazards Zones map, and the initial impacts related to earthquake- induced landslides are considered low. Landslides are shown on geologic maps and landslides were observed during geologic field reconnaissance in the vicinity of the Haskell Canyon Switching Station site. Constructing the switching station on a landslide would have a high initial impact on the Project.

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 61 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION There is a potential for compressible soils to be present at the Haskell Canyon site. Constructing the switching station on soils known to have a potential for settlement would have a high initial impact to the Project NRCS data regarding the expansive potential of surface soils at the Haskell Canyon site have not been reported. However, based on the potential presence of clay shale units at this site, moderately to highly expansive soils may be present. Constructing the switching station on known expansive soils would have a high initial impact on the Project. NRCS data regarding the corrosive potential of surface soils at the Haskell Canyon site have not been reported. However, corrosive soils may be present at the site, and could have a high initial impact on the Project. There are no data readily available regarding groundwater levels at the Haskell Canyon site. However, shallow groundwater or perched groundwater may be present at the site, and could have a high initial impact to the Project if encountered during construction. The Haskell Canyon site is not located in a dam failure inundation zone, and the initial impacts related to dam failure inundation are considered low.

During the design phase for the switching station site, the potential Project impacts would be evaluated through data review, geologic reconnaissance and subsurface exploration, as appropriate. The results of the site-specific evaluation would be incorporated into the design of the switching station. Through this process, the highly sensitive geologic resources that could be affected would be located and mitigation would be implemented to reduce the impacts to low levels; and the potential geologic and seismic hazards would be considered relative to the construction of the switching station, and mitigation techniques would be developed to reduce the impacts to low levels that would be appropriate for design. With the implementation of the appropriate mitigations, the initial impacts to geologic resources and impacts related to potential seismic and geologic hazards at the switching station site can be reduced to low residual levels.

7.5 EXPANSION OF BARREN RIDGE SWITCHING STATION LADWP proposes expansion of the existing Barren Ridge Switching Station to the east side by 235 feet by 500 feet, for a total station size of 485 feet by 500 feet (5.6 acres). The expansion area of the station would include additional electrical structures for additional lines, a material staging area, a roadway within the station, and a drainage area. Expansion of the existing switching station would be similar to the construction of the Haskell Canyon Switching Station. Site construction activities would consist of installation of reinforced concrete foundations, installation of electrical conduits for equipment power and control, and installation of structures and equipment. Equipment needed for station construction would include backhoes, drill rigs, concrete trucks, flatbeds and trucks. Cranes, man-lifts, portable welding units, line trucks and mechanic trucks would also be utilized.

Evaluation of the affected environment for expansion of the Barren Ridge Switching Station (Barren Ridge) is presented in the Affected Environment section of this preliminary evaluation. In summary, review of referenced soil, geologic, and seismic background data indicates that the Barren Ridge site is underlain by Quaternary alluvial sediments. The USDA soil type underlying the site is mapped as the Arizo gravelly loamy sand, which has a low sensitivity rating based on the slight erosion potential. Distinctive geologic features were not observed at the Barren Ridge site. The site is not crossed by a known active fault, and the potential for surface rupture is considered low. Potential seismic ground shaking at the site is on the order of 0.52g. The site is not located in a liquefaction hazard zone or earthquake-induced landslide hazard zone based on the State of California Seismic Hazards Zones map. There are no landslides at the Barren Ridge site. There are no USDA data available regarding the potential for expansive soils at the site. USDA data indicate a low to moderate corrosive soil potential at the Barren Ridge site. There are no data available regarding groundwater levels at the Barren Ridge site. The Barren Ridge site is not located in a dam failure inundation zone.

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 62 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION Assessment of the potential initial impacts for expansion of the Barren Ridge Switching Station includes the following impact results: The soil sensitivity rating at Barren Ridge has been categorized as low, and the impact of erosion of soils at this site is considered low. Distinctive geologic features were not observed at Barren Ridge, and the initial impact to distinctive geologic features is considered low. The Barren Ridge site is not located in an Earthquake Fault Zone and the initial impacts related to surface fault rupture are considered low. The design PGA for the proposed Barren Ridge station is 0.52g. The ground shaking potential at the station site is considered to have a high initial impact. The Barren Ridge site is not located in a potential liquefaction zone based on the State of California Seismic Hazards Zones map, and the initial impacts related to liquefaction are considered low. The Barren Ridge site is not located in a potential earthquake-induced landslide zone based on the State of California Seismic Hazards Zones map, and the initial impacts related to earthquake- induced landslides are considered low. There are no landslides at the Barren Ridge site. There is a potential for compressible soils to be present at the Barren Ridge site. Constructing the expanded switching station on soils known to have a potential for settlement would have a high initial impact to the Project NRCS data regarding the expansive potential of surface soils at the Barren Ridge site have not been reported. However, based on the sandy nature of the surface soils mapped at the site and observed during field reconnaissance, the expansive potential of the soils at this site is considered low, and is considered to have a low initial impact to the Project. The corrosive soil potential at the Barren Ridge site has been categorized as low for concrete and moderate for steel according to NRCS data. Therefore, corrosive soils may be present at the site, and could have a moderate initial impact on the Project. There are no data available regarding groundwater levels at the Barren Ridge site. However, shallow groundwater or perched groundwater may be present at the site, and could have a high initial impact to the Project if encountered during construction. The Barren Ridge site is not located in a dam failure inundation zone, and the initial impacts related to dam failure inundation are considered low.

During the design phase for the expanded switching station site, the potential Project impacts would be evaluated through data review, geologic reconnaissance and subsurface exploration, as appropriate. The results of the site specific evaluation would be incorporated into the design of the expanded switching station. Through this process, the highly sensitive geologic resources that could be affected would be located and mitigation would be implemented to reduce the impacts to low levels; and the potential geologic and seismic hazards would be considered relative to the construction of the expanded switching station, and mitigation techniques would be developed to reduce the impacts to low levels that would be appropriate for design. With the implementation of the appropriate mitigations, the initial impacts to geologic resources and impacts related to potential seismic and geologic hazards at the expanded switching station site can be reduced to low residual levels.

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 63 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION

8.0 ALTERNATIVES

NEPA and CEQA both require consideration of a reasonable range of alternatives to the Proposed Action that would feasibly attain most of the basic objectives of the Project, but avoid or substantially lessen any of the significant or adverse effects of the Project.

8.1 DEVELOPMENT OF ALTERNATIVES A range of alternatives were identified through a siting analysis, the scoping process, and supplemental studies and consultations. A full discussion of alternatives development can be found in the Alternatives Development Report (POWER 2010).

The regional siting analysis identified nine routing opportunities (Segments A through I) for the new 230 kV transmission line between Barren Ridge Switching Station and the proposed Haskell Canyon Switching Station. Some of the routing opportunities or segments were adjusted or modified based on public input and preliminary environmental review, and preliminary electrical system studies. Each of the nine segments are discussed in detail, including impact analysis, in Section 7.0 of this report. Several of these segments were not used in the formation of alternatives as discussed below.

Segment E was recommended for elimination from analysis in the EIS/EIR. The Segment would require an additional 6.5 miles of transmission line in comparison to the Proposed Action and would not significantly reduce or avoid impacts to air quality, biological, cultural, visual, and water resources. Segment H was also recommended for elimination, due to increased impacts to air quality and noise, along with safety concerns, related to helicopter construction. Cumulative effects for the Project would also increase because of the further disturbance of revegetated and rehabilitated areas and potential for impacts from three transmission line projects in the same vicinity.

Eight routing opportunities (Segments A, B, C, D, F, G, 2a, and I) were combined to create end-to-end routing alternatives for the proposed double-circuit 230 kV transmission line between Barren Ridge Switching Station and the proposed Haskell Canyon Switching Station. In addition to routing segments, each Alternative discussed within this section would include other Project components as discussed earlier within this report. These include the addition of a new circuit on existing towers between Castaic Power Plant and Haskell Canyon, reconductoring of the existing BR-RIN transmission line, construction of a new Haskell Canyon Switching Station, and expansion of the existing Barren Ridge Switching Station. Impact assessment and impact results for each of the other Project components listed above, and which are common to each of the Alternatives, are described in Section 7.0. Descriptions and impact assessment of the routing alternatives follow in the sections below.

8.2 ALTERNATIVES DESCRIPTION The following alternatives were identified as a reasonable range of alternatives to the Project that would feasibly attain most of the basic objectives of the Project, but avoid or substantially lessen any of the significant or adverse effects of the Project.

8.2.1. Action Alternatives In addition to a new double-circuit 230 kV transmission line between the Barren Ridge and Haskell Canyon switching stations, whose route would vary among the action Alternatives, the four action Alternatives would include the following common components: the expansion of the existing Barren Ridge Switching Station, construction of a new Haskell Canyon Switching Station, reconductoring of the existing 230 kV transmission line from the Barren Ridge Switching Station to Rinaldi Substation, and the addition of a new 230 kV circuit on existing towers between the Castaic Power Plant and Haskell Canyon Switching Station. Refer to Figure 8-1.

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 64 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION

FIGURE 8-1. ACTION ALTERNATIVES

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 65 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION Alternative 1 (Segments A, C, and D) The Alternative 1 230 kV double-circuit transmission line comprises the preliminary routing Segments A, C, and D, and is the longest Alternative, at 83 miles long. It would run from the Barren Ridge Switching Station to the unincorporated community of Mojave, while paralleling LADWP’s existing 230 kV BR- RIN and 500 kV PDCI transmission lines. It would continue south-southwest to parallel the Los Angeles Aqueduct to Lancaster Road, where it would travel west to the I-5 utility corridor. It would then run southeast along LADWP’s existing Castaic – Rinaldi corridor to the proposed Haskell Canyon Switching Station.

Helicopter Mitigation Within the ANF where the terrain is steep and access is limited, the USFS would require that the new double-circuit 230 kV structures be constructed with the use of helicopters (such as the Hughes 500 or Bell 212, or Sikorsky Skycrane). Refer to Figure 8-2, the Identified Helicopter Mitigation Locations Map, which illustrates the identified locations for this mitigation. The use of helicopters for the construction of transmission tower structures would eliminate the need for new access roads to structure locations, and would therefore minimize land disturbance associated with crane pads, structure laydown areas, and the trucks and tractors used for delivery of structures to sites. However, the following site and ground disturbing construction activities would be required to construct the new transmission line within the identified helicopter construction areas: portable landing pads, helicopter fly yards/staging areas, tower structure vegetation clearing, guard structures at major crossings, wire stringing sites, pullouts, and temporary access roads.

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 66 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION

FIGURE 8-2. IDENTIFIED HELICOPTER MITIGATION LOCATIONS

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 67 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION Geological Considerations The proposed Alternative 1 route begins at the Barren Ridge Switching Station in the Mojave Desert and travels southwest along the northwestern edge of the Mojave Desert and Antelope Valley crossing areas underlain by Quaternary alluvial deposits. It crosses the San Andreas Fault Rift Zone near the western boundary of the Project study area and then runs southeast over steep mountainous areas in the ANF underlain by areas of Mesozoic granitic rock, and by Plio-Pleistocene non-marine and Tertiary marine sedimentary formations. Quaternary alluvial deposits are present in canyons and drainage areas along Alternative 1. The alternative crosses San Francisquito Canyon near the southern end of Alternative 1 and ends at the proposed Haskell Canyon Switching Station underlain by Tertiary sedimentary formations.

Alternative 1 would cross two active faults with the potential for surface rupture, including the active Garlock fault zone at the beginning of the route near the Barren Ridge Switching Station, and the active San Andreas fault zone. Potential ground shaking along Alternative 1 due to seismic activity would range from 0.30g to 0.60g. Liquefaction hazard zones are located near the southern end of the proposed alternative near the proposed Haskell Canyon Switching Station. Mapped landslides and Earthquake- Induced Landslide Hazard Zones are located in the steep ANF in the southern portion of the alternative. Variable areas of slight to very severe erosion potential exist along the proposed alternative. An area of high expansion potential is located along the existing Castaic – Rinaldi corridor. Areas of low to high corrosive soil potential exist along the proposed alternative. Reported groundwater depths along this proposed alternative are on the order of 138 to 336 feet deep in the Antelope Valley area; a 0.2 mile portion of Alternative 1 has an area of reported shallow groundwater 10 feet deep along the existing Castaic – Rinaldi corridor. 1.5 miles of Alternative 1 are located within a potential dam failure inundation zone due to the proximity to Castaic Lake and Bouquet Reservoir.

A summary of the affected environment for Alternative 1 is presented below in Table 28. In general, Alternative 1 would have lower levels of potential ground shaking than Alternatives 2, 2a and 3; would cross fewer liquefaction zones than proposed Alternatives 2, 2a and 3; would cross fewer potential landslide areas than Alternative 3 and more potential landslide areas than Alternative 2 and 2a; and would cross more areas of severe to very severe erosion potential than Alternatives 2, 2a and 3.

Alternative 2 (Segments A, B, and G) –LADWP’s Proposed Action Alternative 2, LADWP’s Proposed Action, comprises Segments A, B, and G and is 61 miles long. It begins at the Barren Ridge Switching Station and runs south, paralleling LADWP’s existing 230 kV BR- RIN and 500 kV PDCI transmission lines. It travels south from the unincorporated community of Mojave, California through the Antelope Valley and approximately one mile east of the Antelope Valley California Poppy Reserve before continuing onto National Forest System lands and ending at the proposed Haskell Canyon Switching Station. The entire route would remain within designated utility corridors and would parallel existing transmission lines. Refer to Section 1.2, Project Description, for a full description of this Alternative.

Geological Considerations The proposed Alternative 2 route begins at the Barren Ridge Switching Station in the Mojave Desert and travels southwest along the northwestern edge of the Mojave Desert and then runs south across the Antelope Valley traversing areas underlain by Quaternary alluvial deposits. Alternative 2 crosses the steep Ritter Ridge/Portal Ridge area and San Andreas Fault Rift Zone in the Leona Valley where Mesozoic granitic rocks, Pelona Schist and Pliocene sedimentary formations underlie the proposed route. It runs south/southeast over the steep, mountainous ANF and through San Francisquito Canyon, Dry Canyon and Haskell Canyon. The ANF portion of Alternative 2 south of the San Andreas Fault Rift Zone is underlain by areas of Mesozoic granitic rock, Precambrian metamorphic rock, Pelona Schist, Tertiary marine and non-marine sedimentary formations, and Quaternary alluvium.

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 68 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION Alternative 2 would cross two active faults with the potential for surface rupture, including the active Garlock fault zone at the beginning of the route near the Barren Ridge Switching Station, and the active San Andreas fault zone. Potential ground shaking along this alternative due to seismic activity would range from 0.25g to 0.80g. Liquefaction hazard zones are located in the southern Antelope Valley and San Andreas Rift Zone areas. Mapped landslides and Earthquake-Induced Landslide Hazard Zones are located in the steep ANF in the southern portion of the alternative. Variable areas of slight to very severe erosion potential exist along the proposed alternative. Areas of low to high corrosive soil potential exist along the proposed alternative. Reported groundwater depths along this proposed alternative are on the order of 172 to 295 feet deep in the Antelope Valley area, and 10 to 184 feet deep in the ANF. 1.4 miles of Alternative 2 are located within a potential dam failure inundation zone due to the proximity to Fairmont Reservoir and Bouquet Reservoir.

A summary of the affected environment for Alternative 2 is presented below in Table 28. In general, Alternative 2 would have a shorter crossing of the San Andreas fault zone (and therefore would cross fewer miles of Earthquake Fault Zones) than Alternatives 1 and 3; would cross fewer liquefaction zones than Alternative 3 and cross more liquefaction zones than Alternative 1; would cross fewer potential landslide areas than Alternatives 1 and 3 and cross slightly more potential landslide areas that Alternative 2a; and would have fewer areas of severe to very severe erosion potential than Alternatives 1, 2a and 3.

Alternative 2a (Segments A, B, G and 2a) The 230 kV double-circuit transmission line in Alternative 2a comprises the preliminary routing Segments A, B, and G, but includes a re-route (Segment 2a) avoiding the unincorporated community of Green Valley. It is 63 miles long and would be very similar to the Proposed Action (Alternative 2), with 56 miles of the same alignment. Alternative 2a would begin at the Barren Ridge Switching Station and run south, paralleling LADWP’s existing 230 kV BR-RIN and 500 kV PDCI transmission lines. It would travel south from the unincorporated community of Mojave through the Antelope Valley and approximately one mile east of the Antelope Valley California Poppy Reserve before continuing onto NFS lands and ending at the proposed Haskell Canyon Switching Station. The route would remain within designated utility corridors and would parallel existing transmission lines, with the exception of the nearly seven miles that would be routed around the unincorporated community of Green Valley. Segment 2a would create a new utility corridor through the ANF. The re-route would rejoin Segment G south of the unincorporated community of Green Valley before continuing south and ending at the proposed Haskell Canyon Switching Station.

Three-Circuit Tower Mitigation In areas where there are ROW expansion constraints and where LADWP has existing 230 kV transmission lines, LADWP is proposing to construct three-circuit towers to carry the existing BR-RIN circuit and two new BR-HC circuits. This would avoid various impacts including the acquisition of residential property in the unincorporated communities of Willow Springs (milepost 27.1 to 27.6) and Elizabeth Lake and Green Valley (milepost 44.6 to 46 and milepost 50.8 to 51.7). This mitigation would be utilized in the same areas that were identified for Three-Circuit Tower Mitigation for the Proposed Project, with the exception of approximately five miles through the unincorporated community of Green Valley, which would not utilize this mitigation. These areas are illustrated in 1-7, the Three-Circuit Tower Mitigation Map.

Helicopter Mitigation Within the ANF where the terrain is steep and access is limited, the USFS would require that the new double-circuit 230 kV structures be constructed by the use of helicopter. Refer to Figure 8-2, Identified Helicopter Mitigation Locations, which illustrates the identified locations for this mitigation. The use of helicopters for the construction of transmission tower structures would eliminate the need for new access roads to structure locations, and would therefore minimize land disturbance associated with crane pads, structure laydown areas, and the trucks and tractors used for delivery of structures to sites. However, the

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 69 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION following site and ground disturbing construction activities would be required to construct the new transmission line within the identified helicopter construction areas: portable landing pads, helicopter fly yards/staging areas, tower structure vegetation clearing, guard structures at major crossings, wire stringing sites, pullouts, and temporary access roads. The estimated sizes of these auxiliary sites (temporary and permanent) and additional construction information is detailed above in the description of the Proposed Action (Alternative 2) and in Appendix C.

Geological Considerations The Segment 2a portion of Alternative 2a would cross areas of steep terrain along Leona Divide, Grass Mountain and a ridge area north of Portal Canyon where it is predominantly underlain by Mesozoic granitic rock and Precambrian metamorphic rock. Segment 2a would not cross a known active fault. Potential ground shaking along this alternative due to seismic activity would range from 0.60g to 0.80g. No liquefaction hazard zones are mapped along Segment 2a. No landslides are shown on geologic maps reviewed for this evaluation. Earthquake-Induced Landslide Hazard Zones are located on the steep terrain along this alternative. Segment 2a is underlain by areas of severe to very severe erosion potential. Areas of moderate corrosive soil potential exist along the proposed alternative. Groundwater data was not readily available for this alternative in the ANF. No potential dam failure inundation zones are mapped along Segment 2a.

A summary of the affected environment for Alternative 2a is presented below in Table 28. In general, Alternative 2a would have a shorter crossing of the San Andreas fault zone (and therefore would cross fewer miles of Earthquake Fault Zones) than Alternatives 1 and 3; would cross fewer liquefaction zones than Alternative 3 and cross more liquefaction zones than Alternative 1; would cross fewer potential landslide areas than Alternatives 1, 2 and 3; and would cross fewer areas of severe to very severe erosion potential than Alternatives 1 and 3 and cross more potential areas of severe to very severe erosion potential than Alternative 2. In comparing Alternative 2 and 2a, Alternative 2a would cross 0.3 fewer miles of earthquake-induced landslide hazard zones, and would cross 1.9 more miles of severe to very severe erosion potential.

Alternative 3 (Segments A, B, F, and I) The proposed 230 kV double-circuit transmission line in Alternative 3 comprises preliminary routing Segments A, B, F, and I. It is 76 miles long and would begin at the Barren Ridge Switching Station and run south, paralleling LADWP’s existing 230 kV BR-RIN and 500 kV PDCI lines. It would travel south from the unincorporated community of Mojave through the Antelope Valley and approximately one mile east of the Antelope Valley California Poppy Reserve before continuing southeast past SCE’s Antelope Substation. The route would then travel toward the city of Palmdale, parallel to SCE’s existing high- voltage transmission lines. It would make a sharp turn to the south to parallel LADWP’s existing Victorville – Rinaldi 500 kV and Adelanto – Rinaldi 230 kV transmission lines. This Alternative would then parallel these transmission lines west, crossing two miles of the ANF. The Alternative would then parallel LADWP’s 500 kV PDCI line north to the proposed Haskell Canyon Switching Station.

Three-Circuit Tower Mitigation In areas where there are ROW expansion constraints and where LADWP has existing 230 kV transmission lines, LADWP is proposing to construct three-circuit towers to carry the existing BR-RIN circuit and two new BR-HC circuits. This would avoid various impacts including the acquisition of residential property in the unincorporated communities of Willow Springs (milepost 27.1 to 27.6). Please refer to the small inset map on Figure 1-7.

Avenue L Re-route To avoid acquisition of private property, a portion of Alternative 3 from mile marker 45.2 to 46.7 was moved to parallel a smaller distribution line south along 90th Street West and then east along West Avenue ―L.‖ Refer to Figure 8-3, Avenue L Re-route on Alternative 3. ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 70 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION

FIGURE 8-3. AVENUE L RE-ROUTE ON ALTERNATIVE 3

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 71 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION Geological Considerations The proposed Alternative 3 route begins at the Barren Ridge Switching Station in the Mojave Desert and travels southwest along the northwestern edge of the Mojave Desert and then runs south across the Antelope Valley traversing areas underlain by Quaternary alluvial deposits. Alternative 3 crosses the steep Portal Ridge area and San Andreas Fault Rift Zone in the Leona Valley where Pelona Schist predominantly underlies the route. It runs west/southwest over the steep, mountainous Sierra Pelona and through Mint Canyon, Bouquet Canyon and Haskell Canyon. The Sierra Pelona portion of Alternative 3 south of the Antelope Valley is underlain by areas of Pelona Schist, granitic rock, and Tertiary marine and non-marine sedimentary formations. Quaternary alluvial deposits are present in canyons and drainage areas along Alternative 3.

Alternative 3 would cross two active faults with the potential for surface rupture including the active Garlock fault zone at the beginning of the route near the Barren Ridge Switching Station, and the active San Andreas fault zone. Potential ground shaking along this alternative due to seismic activity would range from 0.25g to 0.80g. Liquefaction hazard zones are located in the San Andreas Rift Zone and in low-lying canyon areas in the southern part of the alternative. Mapped landslides and Earthquake-Induced Landslide Hazard Zones are located in the steep Sierra Pelona in the southern portion of the alternative. Variable areas of slight to very severe erosion potential exist along the proposed alternative. Areas of low to high corrosive soil potential exist along the proposed alternative. Reported groundwater depths along this proposed alternative are on the order of 10 to 295 feet deep in the Antelope Valley area, and 10 to 326 feet deep in the portions of the Sierra Pelona and canyon areas in the southern portion of the alternative. 1.7 miles of Alternative 3 are located within a potential dam failure inundation zone due to the proximity to Fairmont Reservoir.

A summary of the affected environment for Alternative 3 is presented below in Table 28. In general, Alternative 3 would cross more liquefaction zones than proposed Alternatives 1 2 and 2a; would cross more potential landslide areas than Alternatives 1, 2 and 2a; and would cross fewer areas of severe to very severe erosion potential than Alternative 1 and cross more areas of severe to very severe erosion potential than Alternatives 2 and 2a.

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 72 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION 8.2.2. Summary Description of Action Alternatives A summary of the affected environment for the proposed action alternatives is shown below in Table 28. Table 28 is presented for comparison of the proposed action alternatives and was created by summarizing the potential geologic and seismic hazards and geologic resources in the affected environment presented in Section 5.0 of this report and in Tables 1 through 13.

TABLE 28 – SUMMARY OF AFFECTED ENVIRONMENT FOR PROPOSED ALTERNATIVES

POTENTIAL GEOLOGIC ALTERNATIVE 1 ALTERNATIVE 2 ALTERNATIVE 2a ALTERNATIVE 3 HAZARD/RESOURCE Principal Geologic Units (Geologic Q, QPc, Tv, Mc, M, Q, QPc, Mc, M, Q, QPc, Mc, M, Q, QPc, Mc, M, Symbol)1 grMz Ep, O, grMz, sch, Ep, O, grMz, sch, grMz, gr-m, sch, pC pC pC USDA Soil Types s1024, s766, s769, s1024, s766, s769, s1024, s766, s769, s1024, s766, s769, (U.S. General Soil Types)2 s1009, s1034, s768, s1009, s768, s1009, s768, s1009, s1054, s1055, s1047, s1054, s1047, s1054, s1054, s1055, s909 s1055, s1056, s1055, s1056, s1057, s909, s1057 s1057 s1059 Distinctive Geologic Features3 None None None 0.4 miles of white tuff marker beds Earthquake Fault Zones (miles)4 1.4 (Garlock) 1.4 (Garlock) 1.4 (Garlock) 1.4 (Garlock) 1.5 (San Andreas) 0.9 (San Andreas) 0.9 (San Andreas) 1.5 (San Andreas) Range of Ground Shaking Potential 0.30 – 0.60 g 0.25 – 0.80 g 0.25 – 0.80 g 0.25 – 0.80 g (% of the acceleration due to gravity)5 Liquefaction Hazard Zones From 1.2 1.9 1.9 10.4 Available Data (miles)6 Potential Mapped Landslide Areas 6.6 0.2 0.2 4.1 From Available Data (miles)7 Potential Earthquake-Induced 5.6 2.6 2.3 18.8 Landslide Areas From Available Data (miles)7 Slight 52.2 43.7 42.7 48.0 Erosion Potential Moderate 4.9 1.9 2.5 7.0 8 Severe to Very (miles) 26.0 15.3 17.2 20.2 Severe High Expansion Potential (miles)9 1.8 0.0 0.0 0.0 Corrosive Low 17.5 5.5 5.5 12.8 Potential Moderate 29.4 23.1 23.6 36.2 (miles)10 High 18.3 17.4 17.4 22.2 Range of Groundwater Depths 138 to 336 172 to 295 172 to 295 10 to 295 (feet)11 (Antelope Valley); (Antelope Valley); (Antelope Valley); (Antelope Valley); 10 (Segment D at 10 to 184 (Angeles 10 to 184 (Angeles 10 to 326 (Angeles milepost 34.8- National Forest) National Forest) National Forest) 35.0) Dam Failure Inundation Areas 1.5 1.4 1.4 1.7 (miles)12 Notes: 1 See Table 1 for Description of Geologic Symbol; 2 See Table 3 for U.S. General Soil Types; 3 See Table 4; 4 See Table 5; 5 See Table 6; 6 See Table 7; 7 See Table 8; 8 See Table 9; 9 See Table 10; 10 See Table 11; 11 See Table 12; 12 See Table 13;* Centerline of alignment not finalized.

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 73 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION 8.2.3. No Action Alternative Under the No Action Alternative, the construction of a new 230 kV transmission line, the addition of a new circuit on existing structures from Haskell Canyon to the Castaic Power Plant, the reconductoring of the existing BR-RIN transmission line, the construction of a new Haskell Canyon Switching Station, and the expansion of the existing Barren Ridge Switching Station would not occur. LADWP currently maintains an estimated 147 miles of existing access roads in the Project area, 97 of which are located within the ANF. Current, on-going operation and maintenance activates for existing facilities in the Project area would continue. The EIS/EIR must address the resulting environmental effects from taking no action and compare them to the effects of permitting the Proposed Action or an Alternative to the Proposed Action.

8.3 IMPACT ASSESSMENT—ROUTING ALTERNATIVES A comparison summary of the initial impacts affecting the proposed alternatives is presented in the following section. The proposed routing alternatives were evaluated by adding the miles of impacts in the various geologic resource and potential geologic/seismic hazard categories for the Project segments that comprise the alternatives. Alternative 1 was evaluated by adding the impacts for Segments A, C and D; Alternative 2a was evaluated by adding the impacts for Segments A, B, G, and 2a; and Alternative 3 was evaluated by adding the impacts for Segments A, B, F and I.

8.4 IMPACT RESULTS—ROUTING ALTERNATIVES A comparison summary of the initial impacts affecting the proposed routing Alternatives 1, 2, 2a and 3 is presented in Tables 29 through 39. The impact of the No Action alternative is also presented in the following tables. A discussion of the results of the impact assessment for the proposed routing alternatives follows each table.

TABLE 29 – SUMMARY OF THE PROPOSED ALTERNATIVE POTENTIAL INITIAL IMPACTS TO SOILS1 MILES OF MODERATE MILES OF LOW SENSITIVITY/ MILES OF HIGH TOTAL LENGTH SENSITIVITY/LOW MODERATE IMPACT SENSITIVITY/HIGH PROPOSED OF IMPACT LEVEL AREAS LEVEL AREAS IMPACT LEVEL AREAS ALTERNATIVE ALTERNATIVE TRAVERSED (PERCENT TRAVERSED TRAVERSED (PERCENT (MILES) OF TOTAL LENGTH) (PERCENT OF TOTAL OF TOTAL LENGTH) LENGTH) Alternative 1 83.1 52.2 (62.8%) 4.9 (5.9%) 26.0 (31.3%) Alternative 2 60.7 43.7 (71.8%) 1.9 (3.1%) 15.3 (25.1%) Alternative 2a 62.5 42.7 (68.4%) 2.5 (4.0%) 17.2 (27.6%) Alternative 3 75.5 48.0 (63.8%) 7.0 (9.3%) 20.2 (26.9%) No Action 0.0 0.0 0.0 0.0 Notes: 1 Data from USDA 2008d.

Table 29 shows that Alternative 2 would have fewer miles (and lower percent of total length) of high impact to highly sensitive soils than Alternatives 1, 2a and 3. Alternative 1 would have more miles of high impact (and higher percent of total length) than the other proposed alternatives.

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TABLE 30 – SUMMARY OF THE PROPOSED ALTERNATIVE POTENTIAL INITIAL IMPACTS TO DISTINCTIVE GEOLOGIC FEATURES1 PROPOSED TOTAL LENGTH LOW IMPACT LEVEL MODERATE IMPACT HIGH IMPACT LEVEL ALTERNATIVE OF ALTERNATIVE AREAS TRAVERSED LEVEL AREAS AREAS TRAVERSED (MILES) (MILES) TRAVERSED (MILES) (MILES) Alternative 1 83.1 51.9 31.2 0.0 Alternative 2 60.7 44.2 16.7 0.0 Alternative 2a 62.5 44.2 18.2 0.0 Alternative 3 75.5 49.6 23.7 0.4 No Action 0.0 0.0 0.0 0.0 Notes: 1 Dibblee, 1997c, 1997f, 2002b. field observations.

Table 30 shows that Alternative 3 would have 0.4 mile of high impact to distinctive geologic features, while Alternatives 1, 2 and 2a would not traverse areas of high impact to distinctive geologic features. Due to its shorter total length, Alternative 2 would have fewer miles of moderate level impact to distinctive geologic features than Alternatives 1, 2a and 3.

TABLE 31 – SUMMARY OF THE PROPOSED ALTERNATIVE POTENTIAL INITIAL IMPACTS DUE TO EARTHQUAKE FAULT ZONES PROPOSED TOTAL LENGTH OF ALTERNATIVE HIGH IMPACT LEVEL EARTHQUAKE FAULT ALTERNATIVE (MILES) ZONES TRAVERSED (MILES)1 Alternative 1 83.1 2.9 Alternative 2 60.7 2.3 Alternative 2a 62.5 2.3 Alternative 3 75.5 2.9 No Action 0.0 None Notes: 1 Hart and Bryant, 1997. (formerly Alquist-Priolo Special Studies Zones)

Table 31 shows that Alternatives 2 and 2a would traverse fewer miles of high impact earthquake fault zones than both Alternatives 1 and 3. This is due in part to the manner in which the proposed alternatives traverse the San Andreas fault zone, wherein Alternatives 2 and 2a cross perpendicular to the fault zone and Alternatives 1 and 3 traverse diagonally.

TABLE 32 – SUMMARY OF THE PROPOSED ALTERNATIVE POTENTIAL INITIAL IMPACTS DUE TO GROUND SHAKING

APPROXIMATE MODERATE GROUND SHAKING TOTAL LOW IMPACT HIGH IMPACT IMPACT LEVEL PROPOSED POTENTIAL1 LENGTH OF LEVEL AREAS LEVEL AREAS AREAS ALTERNATIVE (% OF THE ALTERNATIVE TRAVERSED TRAVERSED TRAVERSED ACCELERATION DUE (MILES) (MILES) (MILES) (MILES) TO GRAVITY, g) Alternative 1 0.30 – 0.60 83.1 0.0 69.7 13.4 Alternative 2 0.25 – 0.80 60.7 2.7 48.2 10.0 Alternative 2a 0.25 – 0.80 62.5 2.7 43.4 16.3 Alternative 3 0.25 – 0.80 75.5 2.7 55.9 16.6 No Action N/A 0.0 0.0 0.0 0.0 Notes: 1 USGS (2002rev) data; and USGS (2008) Ground Motion Calculator (for Switching Stations).

Table 32 shows that Alternative 2 would traverse fewer miles of high impact ground shaking areas than Alternatives 1, 2a and 3. This is due in part to the manner in which the proposed alternatives traverse the ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 75 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION ground shaking level contours in the southern part of the Project study area shown on Figure 6. The ground shaking level contours shown on Figure 6 are roughly parallel to the alignment of the San Andreas fault zone, and higher levels of ground shaking occur closer to the fault zone. Since Alternatives 2 and 2a cross roughly perpendicular to the San Andreas fault zone, they depart from the high ground shaking areas in a shorter distance and have fewer miles of high impact areas. Conversely, Alternatives 1 and 3 traverse diagonally to the San Andreas fault zone, and have a longer distance of departure from the high impact areas. Alternative 2a has more miles of high impact areas traversed than Alternative 2 due to the alignment of Segment 2a, which also has a roughly diagonal orientation to the San Andreas fault zone.

TABLE 33 – SUMMARY OF THE PROPOSED ALTERNATIVE POTENTIAL INITIAL IMPACTS DUE TO LIQUEFACTION HAZARD ZONES PROPOSED RATIO OF ALTERNATIVE TOTAL LENGTH OF HIGH IMPACT LEVEL LIQUEFACTION AVAILABLE DATA ALTERNATIVE LIQUEFACTION HAZARD ZONES TO (MILES)1 (MILES) ZONES TRAVERSED (MILES)1 AVAILABLE DATA Alternative 1 83.1 8.8 1.2 13.6% Alternative 2 60.7 16.2 1.9 11.7% Alternative 2a 62.5 18.6 1.9 10.2% Alternative 3 75.5 41.7 10.4 24.9% No Action 0.0 0.0 None 0.0% Notes: 1 Data from CGS Seismic Hazards Mapping Program for available quadrangles in the study area (some quadrangles and data not available

Table 33 shows that Alternative 1 would traverse fewer miles of high impact liquefaction hazard zones than Alternatives 2, 2a and 3. However, Alternative 1 also has fewer miles of available liquefaction zone data than the other alternatives, and when comparing the ratio of miles of liquefaction zones to the miles of available data along the proposed alternatives, the data show that Alternative 2a would have a lower ratio percentage of liquefaction zones than the other proposed alternatives. The data show that Alternative 2 would have a lower ratio percentage than Alternatives 1 and 3. Alternative 3 would traverse more miles and has a higher ratio percentage of liquefaction zones than the other proposed alternatives.

TABLE 34 – SUMMARY OF THE PROPOSED ALTERNATIVE POTENTIAL INITIAL IMPACTS DUE TO MAPPED LANDSLIDES PROPOSED TOTAL LENGTH HIGH IMPACT LEVEL RATIO OF MAPPED ALTERNATIVE OF AVAILABLE DATA LANDSLIDE AREAS LANDSLIDES TO ALTERNATIVE (MILES)1 TRAVERSED (MILES)1 AVAILABLE DATA (MILES) Alternative 1 83.1 26.0 6.6 25.4% Alternative 2 60.7 27.4 0.2 0.7% Alternative 2a 62.5 28.9 0.2 0.7% Alternative 3 75.5 35.5 4.1 11.5% No Action 0.0 0.0 None 0.0% Notes: 1 Data from available geologic maps by Dibblee; and from CGS Seismic Hazards Zones Reports for available quadrangles in the study area (some quadrangles and data not available).

Table 34 shows that Alternatives 2 and 2a would traverse fewer miles of high impact mapped landslide areas than Alternatives 1 and 3. In addition, when comparing the ratio of miles of mapped landslide areas to the miles of available data along the proposed alternatives, the data show that Alternatives 2 and 2a would have a lower ratio percentage of mapped landslide areas than the other proposed alternatives. The

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TABLE 35 – SUMMARY OF THE PROPOSED ALTERNATIVE POTENTIAL INITIAL IMPACTS DUE TO EARTHQUAKE-INDUCED LANDSLIDE HAZARD ZONES RATIO OF TOTAL LENGTH HIGH IMPACT LEVEL EARTHQUAKE- PROPOSED OF AVAILABLE DATA EARTHQUAKE-INDUCED INDUCED LANDSLIDE ALTERNATIVE ALTERNATIVE (MILES)1 LANDSLIDE AREAS AREAS TO (MILES) TRAVERSED (MILES)1 AVAILABLE DATA Alternative 1 83.1 8.8 5.6 63.6% Alternative 2 60.7 16.2 2.6 16.0% Alternative 2a 62.5 18.6 2.3 12.4% Alternative 3 75.5 41.7 18.8 45.1% No Action 0.0 0.0 None 0.0% Notes: 1 Data from CGS Seismic Hazards Zones Reports for available quadrangles in the study area (some quadrangles and data not available).

Table 35 shows that Alternative 2a would traverse fewer miles of high impact earthquake-induced landslide hazard zones than Alternatives 1, 2 and 3. In addition, when comparing the ratio of miles of earthquake-induced landslide hazard zones to the miles of available data along the proposed alternatives, the data show that Alternative 2a would have a lower ratio percentage of earthquake-induced landslide hazard zones than the other proposed alternatives. The data show that Alternative 3 would traverse more miles of earthquake-induced landslide hazard zones than the other proposed alternatives. When comparing the ratio of miles of earthquake-induced landslide hazard zones to the miles of available data, the data show that Alternative 1 has a higher ratio percentage of earthquake-induced landslide hazard zones than the other proposed alternatives.

TABLE 36 – SUMMARY OF THE PROPOSED ALTERNATIVE POTENTIAL INITIAL IMPACTS DUE TO SOIL EROSION1 PROPOSED MILES OF LOW MILES OF MODERATE MILES OF HIGH IMPACT ALTERNATIVE TOTAL LENGTH IMPACT LEVEL IMPACT LEVEL LEVEL AREAS OF ALTERNATIVE AREAS TRAVERSED AREAS TRAVERSED TRAVERSED (PERCENT (MILES) (PERCENT OF TOTAL (PERCENT OF TOTAL OF TOTAL LENGTH) LENGTH) LENGTH) Alternative 1 83.1 52.2 (62.8%) 4.9 (5.9%) 26.0 (31.3%) Alternative 2 60.7 43.7 (71.8%) 1.9 (3.1%) 15.3 (25.1%) Alternative 2a 62.5 42.7 (68.4%) 2.5 (4.0%) 17.2 (27.6%) Alternative 3 75.5 48.0 (63.8%) 7.0 (9.3%) 20.2 (26.9%) No Action 0.0 0.0 0.0 0.0 Notes: 1 Data from USDA(2008d).

Table 36 shows that Alternative 2 would traverse fewer miles of high impact soil erosion areas than Alternatives 1, 2a and 3. In addition, when comparing the percentage of high impact areas to the total length of the alternatives, the data further show that Alternative 2 would have a lower percentage of high impact soil erosion areas than the other proposed alternatives. The data show that Alternative 1 would traverse more miles and have a higher percentage of high impact soil erosion areas than the other proposed alternatives.

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TABLE 37 – SUMMARY OF THE PROPOSED ALTERNATIVE POTENTIAL INITIAL IMPACTS DUE TO CORROSIVE SOILS1 HIGH MODERATE TOTAL LENGTH LOW IMPACT IMPACT AREAS WITH IMPACT PROPOSED OF CORROSIVE SOIL CORROSIVE AVAILABLE DATA CORROSIVE SOIL ALTERNATIVE ALTERNATIVE POTENTIAL SOIL (MILES) POTENTIAL (MILES) (MILES) POTENTIAL (MILES) (MILES) Alternative 1 83.1 65.1 17.5 29.3 18.3 Alternative 2 60.7 45.9 5.5 23.0 17.4 Alternative 2a 62.5 46.5 5.5 23.6 17.4 Alternative 3 75.5 71.1 12.8 36.1 22.2 No Action 0.0 0.0 0.0 0.0 0.0 Notes: 1 Data from USDA (2007b, and 2008a, b, c and d). When multiple soils occur in a single 1/10th mile, the higher potential impact corrosive value is considered.

Table 37 shows that Alternatives 2 and 2a would traverse fewer miles of high impact corrosive soil areas than Alternatives 1 and 3. This is partly due to the shorter length of Alternatives 2 and 2a and the less availability of data. The data show that Alternative 3 would traverse more miles of high impact corrosive soil areas than the other proposed alternatives. This is partly due to the longer distance of Alternative 3, relative to Alternatives 2 and 2a, and the availability of more data for Alternative 3.

TABLE 38 – SUMMARY OF THE PROPOSED ALTERNATIVE POTENTIAL INITIAL IMPACTS DUE TO GROUNDWATER1

MODERATE TOTAL LENGTH LOW IMPACT HIGH IMPACT AREAS WITH IMPACT LEVEL PROPOSED OF LEVEL AREAS LEVEL AREAS AVAILABLE AREAS ALTERNATIVE ALTERNATIVE TRAVERSED TRAVERSED DATA (MILES) TRAVERSED (MILES) (MILES) (MILES) (MILES) Alternative 1 83.1 0.6 0.4 0.0 0.2 Alternative 2 60.7 4.1 2.7 0.1 1.3 Alternative 2a 62.5 4.1 2.7 0.1 1.3 Alternative 3 75.5 8.3 2.9 0.0 5.4 No Action 0.0 0.0 0.0 0.0 0.0 Notes: 1 CDWR, 2008; CGS Seismic Hazards Evaluation Reports.

Table 38 shows that Alternative 1 would traverse fewer miles of high impact groundwater areas than Alternatives 2, 2a and 3. However, Alternative 1 has much less available data than the other proposed alternatives. The data show that Alternative 3 would traverse more miles of high impact groundwater areas than Alternatives 1, 2 and 2a. However, Alternative 3 has much more available data than the other proposed alternatives.

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TABLE 39 – SUMMARY OF THE PROPOSED ALTERNATIVE POTENTIAL INITIAL IMPACTS DUE TO DAM FAILURE INUNDATION PROPOSED TOTAL LENGTH OF ALTERNATIVE HIGH IMPACT LEVEL INUNDATION AREAS ALTERNATIVE (MILES) TRAVERSED (MILES)1 Alternative 1 83.1 1.5 Alternative 2 60.7 1.4 Alternative 2a 62.5 1.4 Alternative 3 75.5 0.9 No Action 0.0 None Notes: 1 Data from County of Los Angeles, 1990; Kern County, 2005; Kern County, 2007.

Table 39 shows that Alternative 3 would traverse fewer miles of high impact level dam failure inundation areas than Alternatives 1, 2, and 2a. The difference in impact areas is due to the geographic extent of the Alternatives relative to mapped dam failure inundation zones.

8.5 NO ACTION ALTERNATIVE Selection of the No Action Alternative would mean that the BRRTP, as proposed, would not be implemented. As such, potential geologic resources in the affected environment, including highly erosion- sensitive soils and distinctive geologic features, would not be impacted by construction of the proposed Project. However, in the absence of the proposed Project, the purposes and need for the power transmission capabilities that would be met by the Project would not be achieved.

Environmental conditions in the Project study area are expected to naturally change or evolve over time. Therefore, independent of the proposed BRRTP, the potential geologic resources in the Project area would not remain static. If the No Action Alternative is selected, the potential geologic resources preserved in the natural environment by not implementing the Project may remain unchanged over a short geologic time period. However, the potential geologic resources would eventually be affected by long- term, natural geologic processes, independent of the potential impacts associated with the proposed BRRTP.

8.6 CUMULATIVE IMPACTS 8.6.1. Introduction Cumulative effects are those effects that result from incremental impacts of the proposed action when added to other past, present and reasonably foreseeable future actions. Analysis of cumulative effects places project-specific impacts into a broader context that takes into account the full range of impacts of actions taking place over a given space and time. Cumulative effects may be considered a significant impact to the environment, as degradation of important resources may result from the combined, incremental effects of actions. Cumulative effects may result from individually minor or insignificant actions, which collectively may be considered significant as they accumulate over time and space from one or more actions or sources.

8.6.2. Impacting Factors Cumulative impacts for geologic resources in the Project study area apply to highly erosion-sensitive soils and distinctive geologic features that may be impacted by the BRRTP. Impacting factors that may affect highly erosion-sensitive soils and highly distinctive geologic features could occur during grading and construction of components of the proposed BRRTP. Erosion of highly sensitive soils could also occur during long-term operation of the BRRTP.

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 79 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION Cumulative impacts related to the major geologic and seismic hazards that may affect the Project apply to surface fault rupture, seismic ground shaking, liquefaction, landslides, soil erosion, settlement, expansive soils, corrosive soils, and groundwater. The impacting factors related to potential geologic and seismic hazards occur due to conditions that may affect the proposed Project from the natural geologic environment.

8.6.3. Impact Area The geographic areas for considering cumulative impacts related to geologic resources and potential geologic and seismic hazards are the proposed Project study corridors, including the expanded Barren Ridge and proposed new Haskell Canyon switching station locations. This is because geologic conditions and potential resources occur at site-specific locales, and are generally not affected by activities occurring outside the corridors.

8.6.4. Cumulative Projects List – Major Present and Reasonably Foreseeable Future Actions The cumulative projects list is used to provide a general context for the cumulative effects. This list includes present and reasonably foreseeable future actions in the Project vicinity that have the potential to combine with the Proposed Action or Alternatives. While a distinct impact area for cumulative impacts and specific present and reasonably foreseeable actions is determined individually for each resource area, collectively, the projects listed below represent the major known and anticipated activities that may occur in the general Project area. The Cumulative Projects Map (Figure 8-4) illustrates the location of energy infrastructure and other major projects in reference to the Proposed Action and Alternatives.

As the project list comprises projects in various stages of planning and development, it is likely that some of these projects would be completed as currently proposed while others would not. To be conservative, the cumulative analysis assumes that all projects listed would be built and in operation during the operating lifetime of the proposed Project. The list was developed in consultation with the following agencies:

USFS – Angeles National Forest (ANF) BLM – Ridgecrest Field Office BLM – Palm Springs Field Office United States Air Force – Edwards Air Force Base Kern County – Planning Department Los Angeles County – Department of Regional Planning City of California City City of Lancaster City of Palmdale City of Santa Clarita City of Los Angeles City of San Fernando LADWP

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FIGURE 8-4. CUMULATIVE PROJECTS

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ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 82 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION Energy Infrastructure Projects Transmission Projects Antelope Transmission Project – Construction of Southern California Edison’s (SCE) proposed Antelope Transmission Project is underway and is proceeding in three sequential segments. Construction of Segments 1, 2 and 3A have been completed. Construction of Segment 3B, from Windhub Substation to and including Highwind Substation, has not started and no schedule has been developed by SCE (California Public Utilities – Current Projects).

Segment 1, Antelope – Pardee 500 kV Transmission Line, involved the construction of a new 25.6-mile transmission line between SCE’s existing Antelope Substation in the city of Lancaster and SCE’s existing Pardee Substation in Santa Clarita, with modifications to and/or expansion of the substations. The line was constructed in an existing SCE 66 kV transmission line right-of-way (ROW) for 23 miles, and within a new ROW for 18 miles. The line is initially energized to 220 kV to serve existing energy demand and can be upgraded to 500 kV to accommodate future needs.

Segment 2, Antelope – Vincent 500 kV Transmission Line, consists of a new 17.8 mile transmission line between the Antelope Substation and SCE’s existing Vincent Substation near Acton. Similar to Segment 1, the line would initially be energized at 220 kV and upgraded to meet future needs.

Segment 3, Antelope – Tehachapi Transmission Line, consists of two phases. The first phase, 3A, would involve the construction of a new 26.1-mile 500 kV transmission line between the Antelope Substation and a proposed new substation in the vicinity of the unincorporated community of Mojave (Substation 1). Similar to Segments 1 and 2, this line would be initially energized at 220 kV and upgraded to meet future needs. The second phase, 3B, would involve the construction of a new 9.4-mile 220 kV transmission line from the proposed Substation 1 to a proposed new substation in the Monolith area (Substation 2).

Tehachapi Renewable Transmission Project (TRTP) – SCE is proposing to construct the TRTP, which would involve new and upgraded transmission infrastructure along 173 miles of new and existing rights- of-way, in southern Kern County, portions of Los Angeles County including the ANF, and the southwestern portion of San Bernardino County. Stated objectives for the project include providing the electrical facilities necessary to integrate levels of wind generation in excess of 700 MW and up to 4,500 MW in the Tehachapi Wind Resource Area (California Public Utilities – Current Projects).

The environmental review process for the project is currently underway. Construction began in April 2010 on approved sections. Project construction is estimated to be completed in 2015.

The project is composed of Segments 4 through 11, with Segments 4 through 8 and Segments 10 and 11 being transmission facilities, and Segment 9 being the addition and upgrade of substation facilities. Proposed transmission lines would be constructed primarily within existing rights-of-way. Major project components include:

Constructing two new single-circuit 220 kV transmission lines within 4 miles of new ROW between the Cottonwood Substation and proposed Whirlwind Substation (Segment 4); Constructing a new single-circuit 500 kV transmission line within 16 miles of new ROW between the Antelope Substation and proposed Whirlwind Substation (Segment 4); Rebuilding 18 miles of the existing Antelope – Vincent and Antelope – Mesa 220 kV transmission lines to 500 kV standards within existing ROW between the Antelope and Vincent Substations (Segment 5); Rebuilding 27 miles of the existing Antelope – Mesa 220 kV transmission line and 5 miles of the existing Rio Hondo – Vincent 220 kV transmission line to 500 kV standards between the Vincent Substation and the southern boundary of the ANF (Segment 6);

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 83 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION Rebuilding 16 miles of the existing Antelope – Mesa 220 kV transmission line to 500 kV standards between the southern boundary of the ANF and Mesa Substation (Segment 7); Rebuilding 33 miles of the existing Chino – Mesa 200 kV transmission line to 500 kV standards between a point 2 miles east of the Mesa Substation and the Mira Loma Substation (Segment 8); Rebuilding 7 miles of the existing Chino – Mira Loma No. 1 220 kV transmission line from single-circuit to double-circuit structures (Segment 8); Constructing a new 500/220 kV Whirlwind Substation 4 to 5 miles south of the Cottonwood Substation (Segment 9); Upgrading the existing Antelope, Vincent, Mesa, Gould, and Mira Loma Substations to accommodate new transmission line construction and system compensation elements (Segment 9); Constructing a new single-circuit 500 kV transmission line within 17 miles of new ROW between the Windhub Substation and proposed Whirlwind Substation (Segment 10); Rebuilding 19 miles of existing 220 kV transmission line to 500 kV standards in existing ROW between the Vincent and Gould Substations (Segment 11); Adding a new 220 kV circuit between the Mesa and Gould Substations on the vacant side of the existing Eagle Rock – Mesa 220 kV transmission line double circuit structures (Segment 11); and Installing associated telecommunications infrastructure.

Generation Projects Numerous wind and solar generation projects are in various stages of planning and development within the Project vicinity. Projects considered include the projects currently undergoing environmental review or projects that have been recently approved. Table 8a below summarizes the major known projects and their current status as of April 2011 (County of Kern Environmental Documents and AV Solar Ranch One).

TABLE 8A. PROPOSED GENERATION PROJECTS IN THE PROJECT VICINITY

Approximate Area Project Name Project Type Location Status Generation (acres) Application to Kern County Alta East Wind Project Wind 300 MW 3,660 Kern County deemed complete on Aug. 2010 Alta Wind Energy Center: Approved by Kern County Alta-Oak Creek Mojave Wind Turbine 800 MW 9,175 Kern County Dec. 2009 Project Draft EIR released April Antelope Valley Solar Project Solar Photovoltaic 650 MW 5,698 Kern County 2011 Los Angeles Final EIR completed Aug. AV Solar Ranch One Solar Photovoltaic 230 MW 21,000 County 2010 Application to Kern County Avalon Wind Project Wind 255 MW 10,000 Kern County deemed complete on July 2010 Concentrated Application for Certification Beacon Solar Energy Project 250 MW 2,012 Kern County Solar approved Aug. 2010 Catalina Renewable Energy Wind Turbine & Notice of Preparation for a 350 MW 7,472 Kern County Project Solar Photovoltaic Draft EIR filed Feb. 2011 Draft EIR released Nov. Clearvista Wind Project Wind Turbine 40 MW 226 Kern County 2010 Edwards Air Force Base Solar Lease execution anticipated Solar 500 MW 3,288 Kern County Project 2012

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Approximate Area Project Name Project Type Location Status Generation (acres) Lower West Wind Energy Draft EIR released April Wind Turbine 14 MW 185 Kern County Project 2011 Notice of Preparation for a Monte Vista Solar Array Solar Photovoltaic 126 MW 1,040 Kern County Draft EIR filed March 2010 Application submitted Nov. Morgan Hills Wind Project Wind 230 MW 3,604 Kern County 2010 Notice of Preparation for a North Sky River Wind Project Wind Turbine 326 MW 1,330 Kern County Draft EIR filed Nov. 2010 Approved by Kern County Pacific Wind Energy Project Wind Turbine 151 MW 8,300 Kern County Oct. 2010 Pahnamid Wind Energy Notice of Preparation for a Wind Turbine 411 MW 7,106 Kern County Project Draft EIR filed April 2011 Approved by Kern County PdV Wind Energy Project Wind Turbine 300 MW 5,820 Kern County July 2008 Pine Canyon Wind Project Wind Turbine 150 MW 12,000 Kern County Preliminary planning Pine Tree Solar Project Solar Photovoltaic 10 MW 75 Kern County Preliminary planning Pine Tree Wind & Expansion Wind Turbine 135 MW n/a Kern County Preliminary planning Notice of Preparation for a RE Distributed Solar Project Solar Photovoltaic 221 MW 1,709 Kern County Draft EIR filed Jan. 2011 Ridge Rider Solar Park Notice of Preparation of a Solar Photovoltaic 38 MW 475 Kern County Project Draft EIR filed March 2010 Notice of Intent to prepare a Rising Tree Wind Farm Wind Turbine 234 MW 2,745 Kern County EIS/EIR filed Jan. 2011 Notice of Preparation of a Rosamond Solar Array Solar Photovoltaic 155 MW 1,177 Kern County Draft EIR filed March 2010 Approved by Kern County Rosamond Solar Project Solar Photovoltaic 120 MW 960 Kern County Nov. 2010 Notice of Preparation of a Sand Canyon Wind Projects Wind Turbine 40 MW 300 Kern County Draft EIR filed Oct. 2010 Willow Springs Solar Array Notice of Preparation of a Solar Photovoltaic 160 MW 1,402 Kern County Project Draft EIR filed March 2010 Approved by Kern County Windstar Wind Energy Project Wind Turbine 65 MW 1,007 Kern County April 2009

There are also plans in various stages of development to establish additional wind and solar energy projects on BLM land in the Project vicinity. The submission of an application to BLM is a preliminary step in the project planning process, but not all applications ultimately result in successful project development. Below is a list of current applications for wind and solar energy generation projects in the Project vicinity submitted to BLM’s Ridgecrest Field Office as of February 2010 (U.S. Department of the Interior, Bureau of Land Management – Renewable Energy).

TABLE 8B. BLM RIDGECREST OFFICE APPLICATIONS FOR WIND AND SOLAR ENERGY GENERATION PROJECTS IN THE PROJECT VICINITY. Date Application Serial Received, Approximate Applicant Project Type Location Number ROW Grant Issued, Area (Acres) Last Amended Date CACA Sean Roberts, Renewable Land LLC 7/1/04 528 Pending Wind Mojave 46978 CACA Oak Creek Energy 1/11/06 7,349 Pending Wind Lucchese 47848 Soledad CACA Oak Creek Energy 7/25/06 1,800 Pending Wind Mountain Wind 48536 Project

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Date Application Serial Received, Approximate Applicant Project Type Location Number ROW Grant Issued, Area (Acres) Last Amended Date CACA First Solar (Formally OptiSolar Inc.) 12/13/08 5,760 Pending Solar Mojave Area 48820 CACA Power Partners SW (enXco) 8/10/07 1,816 Pending Wind Soledad area 49577 CACA AES SEAWEST INC 7/3/09 120 Pending Wind Kern County 50171 CACA Riverside Wind Energy LLC 4/20/09 480 Pending Wind Gorman 50768 CACA Advanced Dev Services, Inc 4/30/09 11,174 Pending Wind Kern County 51016 CACA Alta Windpower Dev., LLC 7/13/09 584 Pending Wind Kern County 51335 CACA Power Partners Southwest 12/11/09 1,160 Pending Wind Kern County 51561

Other Major Projects Transportation and Public Facilities California High Speed Rail – This project proposes a ±700-mile high speed rail line from Sacramento to San Diego. The Statewide Programmatic EIS/EIR was completed in 2005, and the Bay Area to Central Valley High-Speed Train Program EIS/EIR was completed in 2008. Multiple second-tier project-level environmental documents (with preliminary engineering design) are currently underway (California High Speed Rail Authority).

Pacific Pipeline Storm Relocation Project and Access Road Repairs – Pacific Pipeline is proposing to relocate several miles of crude oil pipeline to more stable ground within the ANF. Project implementation was expected in November 2010 (Forest Service Schedule of Proposed Actions for the Angeles National Forest).

Antelope Valley Water Bank Project – This project proposes to develop facilities to store and recharge imported surface water and associated delivery and distribution pipelines. The 13,440-acre facility area would be bounded by the Kern/Los Angeles County border line (also known as Avenue A) to the south and Rosamond Boulevard to the north, and between 170th Street West and 100th Street West in unincorporated Kern County (U.S. Department of the Interior, Bureau of Reclamation – Mid-Pacific Region).

Soledad Canyon Cemex Project – The Soledad Canyon Cemex project would be a 56-million-ton sand and gravel mining project in the Soledad Canyon area. The BLM approved the project with mitigating measures in 2000, and the Interior Board of Land Appeals affirmed that decision in 2002. A City of Santa Clarita challenge to the US Supreme Court was denied in 2006. This project is pending development with ongoing challenges and delays (Cemex United States).

Community Development Centennial, California – The proposed project site consists of 12,000 acres located one mile east of Interstate 5 (I-5) and adjacent to State Highway 138 in Los Angeles County. The project would include a specific plan and subdivision entitlements (i.e., tract maps and conditional use permits) for a master planned community. The specific plan proposes a maximum of 23,000 dwelling units and 14 million total square feet of non-residential development of employment areas (12,233,390 square feet) and retail serving centers (1,986,336 square feet), anticipated to be built over approximately 20 years, with build- out expected in 2030. If the project is approved by Los Angeles County, it is estimated that the non- residential development may generate approximately 31,000 jobs. The draft Specific Plan for the

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Maintenance and Landscape Management Projects Bouquet Canyon Road Realignment – Los Angeles County Department of Public Works is proposing to straighten some sections of Bouquet Canyon Road and to raise the road surface by approximately nine feet. A Memorandum of Understanding between ANF and Los Angeles County is currently under development to initiate the project (Forest Service Schedule of Proposed Actions for the Angeles National Forest).

San Francisquito Road Rehabilitation and Sediment Disposal Site – Los Angeles County Department of Public Works is proposing a road realignment and new bridge along San Francisquito Road within the ANF and to use eight acres of Forest land as a spoils site in support of construction activities. Public Scoping began in June 2007, and a decision was expected in September 2010 (Forest Service Schedule of Proposed Actions for the Angeles National Forest).

Old Ridge Route Storm Damage Repair – USFS is proposing to repair and provide maintenance to seven storm-damaged locations along the Old Ridge Route in ANF. A decision on the project is expected in late 2010 (Forest Service Schedule of Proposed Actions for the Angeles National Forest).

Livestock Grazing Allotments – BLM currently authorizes both cattle and sheep grazing on 11 grazing allotments in and around the project area. The livestock are authorized with 10 year permits/leases and yearly authorizations. These allotments encompass over one half million acres of BLM-managed lands. The number of livestock grazed each year depends upon weather conditions. The majority of the livestock are sheep. The number of sheep average around thirty thousand head. Three of the allotments support several thousand head of cattle (Harris 2010).

Tule Ridge/South Portal Fuels Reduction Project – USFS proposes fuels reduction and re-establishment of a fuel break to provide protection to unincorporated community of Green Valley. The project would also enhance wildlife for mammals and birds (Forest Service Schedule of Proposed Actions for the Angeles National Forest).

Jupiter Fuelbreak Project – USFS proposes to re-establish an existing fuel break that begins southwest of the unincorporated community of Green Valley and travels east, bisecting Jupiter Mountain, before heading south to Bouquet Reservoir.

Santa Clara/Mojave River Rangers District Plantation Maintenance Project – The proposed project would consist of vegetation maintenance at 13 plantations located within the ANF in order to reduce wildfire risk, and improve wildlife habitat and the vitality of individual remaining trees. Proposed actions include removal of dead trees, thinning of live trees, pruning, removing weeds, and planting for reforestation where necessary. This action was approved by the District Ranger in January 2010 (Forest Service Schedule of Proposed Actions for the Angeles National Forest).

Lake Hughes Plantation Restoration Project – The proposed project would restore unauthorized off- highway vehicle trails at the Christian and Taylor Plantations located within the ANF in order to reduce soil erosion, the spread of weeds, destruction of native plants, soil compaction, and wildlife habitat loss. Proposed actions include recontouring and decompacting soils, reseeding with native species, and reinforcing check dams. The project was approved by the District Ranger in 2009 and scheduled for implementation in January 2010 (Forest Service Schedule of Proposed Actions for the Angeles National Forest).

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 87 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION Bouquet and San Francisquito Habitat Improvement Project – The project proposes invasive species removal in Bouquet and San Francisquito Canyons (Forest Service Schedule of Proposed Actions for the Angeles National Forest).

Local Projects In conjunction with the major projects listed above, a summary of local foreseeable projects within the study area that could contribute to cumulative effects are summarized in the table below. These proposed projects were gathered from applications to the planning departments of the various jurisdictions and have been categorized by project type.

TABLE 8C. PROPOSED LOCAL PROJECTS IN THE PROJECT VICINITY. Los City of City of City of City of Kern City of City of Angeles California Santa Los San County Palmdale2 Lancaster County1 City Clarita Angeles Fernando Single Family Residential 1 96 0 14 93 10 2 2 (may include multiple units) Multi Family Residential 28 9 0 9 2 1 2 1 (may include multiple units) Schools 2 2 0 9 2 0 0 0 Religious Uses 10 7 0 13 0 0 1 1 Recreational Facilities 7 5 0 7 1 0 0 1 Public Facilities – police, 2 5 0 4 0 0 0 0 fire, library, correctional Commercial/ Office 40 33 0 96 6 21 2 7 Development Hotels/Motels 1 0 0 9 2 1 1 2 Medical/Care Facilities 4 6 0 16 0 1 0 1 Industrial Facilities 20 0 0 17 1 6 2 2 Mining Operations 15 0 0 4 0 0 0 0 RV Facilities 2 0 0 0 0 0 0 0 Animal Facilities 8 6 0 1 0 0 0 0 Aviation Facilities 2 0 0 0 0 0 0 0 Non-Commercial Energy 1 2 0 0 0 0 0 0 Facilities 1 Projects listed for Los Angeles County include all projects that could contribute to cumulative effects within the following County Districts: Antelope Valley West, Bouquet Canyon, Castaic Canyon, Chatsworth, Lancaster, Leona Valley, Mount Gleason, Newhall, North Palmdale, Palmdale, Quartz Hill, Sand Canyon, Soledad. Some identified projects included may be outside of the study area. 2 Projects listed for the City of Palmdale include all projects that could contribute to cumulative effects within the City. Some identified projects included may be outside of the study area.

8.6.5. Cumulative Impacts Summary Past and ongoing development within the proposed BRRTP area has resulted in alterations to the natural geologic conditions. Past, existing and future projects could contribute cumulative impacts on the geologic resources within the study area by creating erosion of highly sensitive soils and alteration of distinctive geologic features. These potential impacts to geologic resources would be limited to areas within and adjacent to the boundaries of individual projects, and such impacts would have to occur in similar locations within the boundaries of the proposed BRRTP. However, construction of the proposed BRRTP would preclude other projects from being implemented concurrently in the same location. Therefore, proposed Project impacts related to highly erosion-sensitive soils and highly distinctive geologic features would not have the potential to combine with similar impacts from other projects and would not have cumulative impacts.

The major geologic and seismic impacts that may affect the proposed BRRTP (surface fault rupture, seismic ground shaking, liquefaction, landslides, settlement, expansive soils, corrosive soils, and

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 88 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION groundwater) are related to outside effects from the natural environment that may impact the Project, and are not related to impacts from other past, present, or future projects in the study area. The impacts related to surface fault rupture, ground shaking, liquefaction and earthquake-induced landslides are related to earthquakes and would not be due to other projects in the BRRTP impact area. The effects of soil erosion that may impact the Project components are due to the nature of the earth materials, steepness of the terrain and other natural factors that are not related to other projects. Potential settlement, expansive soils and corrosive soils are also related to the inherent natural properties of soils underlying the Project components, and would not be due to effects from other projects. Therefore, the impacts to the BRRTP related to potential geologic and seismic hazards are not considered to have cumulative impacts, since they are not due to other past, present or future projects within the impact area.

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9.0 REFERENCES

Allen, C.R., 1975, Geologic Criteria for Evaluating Seismicity: Geological Society of America Bulletin, v. 86, pp. 1041-1056. Blake, T.F., 2001, FRISKSP (Version 4.00), A Computer Program for the Probabilistic Estimation of Peak Acceleration and Uniform Hazard Spectra Using 3-D Faults as Earthquake Sources. Bonilla, M.G., 1970, Surface Faulting and Related Effects in Wiegel, R.L., Editor, Earthquake Engineering: Prentice Hall, p. 47-74. California Building Code, 2007 Edition, Based on 2006 International Business Code, effective January 1, 2008. California Department of Conservation, Division of Mines and Geology (CDMG), 1962, Mines and Mineral Resources of Kern County, California, County Report 1. California Department of Conservation, Division of Mines and Geology (CDMG), 1983, Guidelines for Classification and Designation of Mineral Lands, Special Publication 51. California Department of Conservation, Division of Mines and Geology (CDMG), 1994, Update of Mineral Land Classification of Portland Cement Concrete Aggregate in Ventura, Los Angeles, and Orange Counties, California, Part II – Los Angeles County, Miller, R.V., Open File Report 94-14. California Department of Conservation, Division of Mines and Geology, State of California, 1998, Seismic Hazards Evaluation of the San Fernando 7.5-Minute Quadrangle, Los Angeles County, California: Open-File Report 98-06. California Department of Conservation, Division of Mines and Geology, State of California, 1999, Seismic Hazards Zones Official Map, San Fernando Quadrangle, 7.5-Minute Series: Scale 1:24,000, Open-File Report 98-06, dated March 25. California Department of Conservation, Division of Mines and Geology, State of California, 2003a, Seismic Hazards Zone Report for the Lake Hughes 7.5-Minute Quadrangle, Los Angeles County, California: Seismic Hazard Zone Report 103. California Department of Conservation, Division of Mines and Geology, State of California, 2003b, Preliminary Report, Seismic Hazard Zone Report for the Rosamond 7.5-Minute Quadrangle, Los Angeles County, California: Seismic Hazard Zone Report 093. California Department of Water Resources (CDWR), 2008, Groundwater Level Data: http:// www.wdl.water.ca.gov California Division of Mines and Geology, 1998, Seismic Hazards Zones Official Map, Newhall 7.5- Minute Quadrangle, Los Angeles County, California, Seismic Hazard Evaluation Open File Report 97-11, dated February 1. California Division of Mines and Geology, 1999, Seismic Hazards Zones Official Map, Mint Canyon 7.5- Minute Quadrangle, Los Angeles County, California, Seismic Hazard Evaluation Open File Report 98-09, dated March 25. California Division of Mines and Geology, 2000, Guidelines for Evaluating the Hazard of Surface Fault Rupture: Division of Mines and Geology Note 49. California Environmental Resources Evaluation System (CERES), 2005a, The California Environmental Quality Act, Title 14; California Code of Regulations, Chapter 3; Guidelines for Implementation of the California Environmental Quality Act, Article 9; Contents of Environmental Impact Reports, Final Text dated May 25, Website: http://ceres.ca.gov/topic/env_law/ceqa/guidelines/ art9.html.

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 90 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION California Environmental Resources Evaluation System (CERES), 2005b, The California Environmental Quality Act, CEQA Guidelines Appendices, Appendix G – Environmental Checklist Form, Final Text dated May 25, Website: http://ceres.ca.gov/topic/env_law/ ceqa/guidelines/appendices.html. California Geological Survey, 2002, Seismic Hazards Zones Official Map, Valverde 7.5-Minute Quadrangle, Los Angeles County, California, Seismic Hazard Zone Report 76, dated December 20. California Geological Survey, 2003a, Seismic Hazards Zones Official Map, Agua Dulce 7.5-Minute Quadrangle, Los Angeles County, California, Seismic Hazard Zone Report 85, dated April 17. California Geological Survey, 2003b, Seismic Hazards Zones Official Map, Whitaker Peak 7.5-Minute Quadrangle, Los Angeles County, California, Seismic Hazard Zone Report 77, dated March 24. California Geological Survey, 2003c, Seismic Hazards Zones Official Map, Ritter Ridge 7.5-Minute Quadrangle, Los Angeles County, California, Seismic Hazard Zone Report 83, dated August 14. California Geological Survey, 2003d, Seismic Hazards Zones Official Map, Sleepy Valley 7.5-Minute Quadrangle, Los Angeles County, California, Seismic Hazard Zone Report 106, dated October 17. California Geological Survey, 2003e, Seismic Hazards Zones Official Map, Lake Hughes 7.5-Minute Quadrangle, Los Angeles County, California, Seismic Hazard Zone Report 103, dated October 17. California Geological Survey, 2005, Seismic Hazards Zones Official Map, Del Sur 7.5-Minute Quadrangle, Los Angeles County, California, Seismic Hazard Zone Report 101, dated February 11. California Geological Survey, 2005, Seismic Hazards Zones Official Map, Lancaster West 7.5-Minute Quadrangle, Los Angeles County, California, Seismic Hazard Zone Report 95, dated February 11. California Geological Survey, 2005, Seismic Hazards Zones Official Map, Rosamond 7.5-Minute Quadrangle, Los Angeles County, California, Seismic Hazard Zone Report 93, dated February 11. California Geological Survey, 2008, Guidelines for Evaluating and Mitigating Seismic Hazards in California: Special Publication 117. Cao, Tianqing, Bryant, William A., Rowshandel, Badie, Branum, David, and Wills, Christopher J., 2003, The Revised 2002 California Probabilistic Seismic Hazard Maps, Adapted by California Geological Survey, dated June. County of Los Angeles Department of Regional Planning, 1990, Los Angeles County Safety Element, Scale 1 inch = 2 miles. Dibblee, Thomas W., Jr., 1967, Aerial Geology of the Western Mojave Desert, California, Geological Survey Professional Paper 522, Scale 1:125,000. Dibblee, T.W., Jr., 1991, Geologic Map of the San Fernando and Van Nuys (North ½) Quadrangles, Los Angeles County, California: Dibblee Foundation, DF-33, Scale 1:24,000. Dibblee, T.W., Jr., 1996, Geologic Map of the Newhall Quadrangle, Los Angeles County, California: Dibblee Foundation, DF-56, Scale 1:24,000. Dibblee, T.W., Jr., 1997a, Geologic Map of the Agua Dulce Quadrangle, Los Angeles County, California: Dibblee Foundation, DF-58, Scale 1:24,000. Dibblee, T.W., Jr., 1997b, Geologic Map of the Green Valley Quadrangle, Los Angeles County, California: Dibblee Foundation, DF-65, Scale 1:24,000. Dibblee, T.W., Jr., 1997c, Geologic Map of the Mint Canyon Quadrangle, Los Angeles County, California: Dibblee Foundation, DF-57, Scale 1:24,000.

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 91 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION Dibblee, T.W., Jr., 1997d, Geologic Map of the Warm Springs Mountain Quadrangle, Los Angeles County, California: Dibblee Foundation, DF-64, Scale 1:24,000. Dibblee, T.W., Jr., 1997e, Geologic Map of the Whitaker Peak Quadrangle, Los Angeles County, California: Dibblee Foundation, DF-63, Scale 1:24,000. Dibblee, T.W., Jr., 1997f, Geologic Map of the Sleepy Valley and Ritter Ridge Quadrangles, Los Angeles County, California: Dibblee Foundation, DF-66, Scale 1:24,000. Dibblee, T.W., Jr., 2002a, Geologic Map of the Black Mountain Quadrangle, Los Angeles and Ventura Counties, California: Dibblee Foundation, DF-92, Scale 1:24,000. Dibblee, T.W., Jr., 2002b, Geologic Map of the Lake Hughes and Del Sur Quadrangles, Los Angeles County, California: Dibblee Foundation, DF-82, Scale 1:24,000. Dibblee, T.W., Jr., 2002c, Geologic Map of the Liebre Mountain Quadrangle, Los Angeles County, California: Dibblee Foundation, DF-93, Scale 1:24,000. Dibblee, T.W., Jr., 2006, Geologic Map of the Frazier Mountain & Lebec Quadrangles, Los Angeles County, California: Dibblee Foundation, DF-198, Scale 1:24,000. Dolan, J.F., Sieh K., Rockwell, T.K., 2000, Late Quaternary Activity and Seismic Potential of the Santa Monica Fault System, Los Angeles, California: Geological Society of America Bulletin, Vol. 112, Issue: 10, pp. 1559-1581, dated October. Google Earth, 2010, http://earth.google.com. Hart, E.W., and Bryant, W.A., 1997, Fault-Rupture Hazard Zones in California, Alquist-Priolo Special Studies Zone Act of 1972 with Index to Special Studies Zones Maps: California Division of Mines and Geology, Special Publication 42. Jennings, C.W., and Strand, R.G., 1969, Geologic Map of California: Los Angeles Sheet, California Division of Mines and Geology, Scale 1:250,000. Jennings, C.W., and Bryant, W.A., 2010, Fault Activity Map of California and Adjacent Areas: California Division of Mines and Geology, California Geologic Data Map Series, Map No. 6, Scale 1:750,000. Kern County, 2005, Multi-Hazard Mitigation Plan, dated November. Kern County, 2007, General Plan, Safety Element, Chapter 4, dated March 13. Kern Master Environmental Assessment Resource, 2004, Flood Plain & Dam Inundation Areas. Los Angeles Department of Water & Power (LADWP), 2008, Draft Barren Ridge Geologic Report Outline and Aerial Reconnaissance Photo Essay, Segments A and D, dated August 11. Norris, R.M., and Webb, R.W., 1990, Geology of California: John Wiley & Sons, 541 pp. POWER Engineers, Inc. 2010, GIS data for project plans and resources. POWER Engineers, Inc. 2010. Barren Ridge Renewable Transmission Project Alternatives Development Report. Prepared for Los Angeles Department of Water and Power, Los Angeles, California. Prepared by POWER Engineers, Inc., Anaheim, California. POWER Engineers, Inc. 2010, LADWP Barren Ridge Renewable Transmission Project, Cumulative Projects – Energy Infrastructure and Other Major Projects, dated February 26. Smith, A.R., 1964, Geologic Map of California, Bakersfield Sheet, Olaf P. Jenkins Edition: California Division of Mines and Geology, Scale 1:250,000. Southern California Earthquake Center (SCEC), 2004, Index of Faults of California: http:// www.data.scec.org/fault_index/, dated June 17.

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 92 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION State of California, 1974a, Special Studies Zones, Burnt Peak Quadrangle, 7.5 Minute Series: Scale 1:24,000. State of California, 1974b, Special Studies Zones, Del Sur Quadrangle, 7.5 Minute Series: Scale 1:24,000, Revised 1979. State of California, 1974c, Special Studies Zones, Lake Hughes Quadrangle, 7.5 Minute Series: Scale 1:24,000. State of California, 1974d, Special Studies Zones, La Liebre Ranch Quadrangle, 7.5 Minute Series: Scale 1:24,000. State of California, 1974e, Special Studies Zones, Lebec Quadrangle, 7.5 Minute Series: Scale 1:24,000. State of California, 1974f, Special Studies Zones, Liebre Mountain Quadrangle, 7.5 Minute Series: Scale 1:24,000. State of California, 1976a, Special Studies Zones, Liebre Twins, 7.5 Minute Series: Scale 1:24,000. State of California, 1976b, Special Studies Zones, Mojave Quadrangle, 7.5 Minute Series: Scale 1:24,000. State of California, 1976c, Special Studies Zones, NE 1/4 Mojave Quadrangle, 7.5 Minute Series: Scale 1:24,000. State of California, 1976d, Special Studies Zones, NW 1/4 Mojave Quadrangle, 7.5 Minute Series: Scale 1:24,000. State of California, 1976e, Special Studies Zones, Monolith Quadrangle, 7.5 Minute Series: Scale 1:24,000. State of California, 1976f, Special Studies Zones, Tehachapi South Quadrangle, 7.5 Minute Series: Scale 1:24,000. State of California, 1976g, Special Studies Zones, Tyler Horse Ridge Quadrangle, 7.5 Minute Series: Scale 1:24,000. State of California, 1979a, Special Studies Zones, Palmdale Quadrangle, 7.5 Minute Series: Scale 1:24,000, dated January 1. State of California, 1979b, Special Studies Zones, Ritter Ridge Quadrangle, 7.5 Minute Series: Scale 1:24,000, dated January 1. State of California, 1979c, Special Studies Zones, Sleepy Valley Quadrangle, 7.5 Minute Series: Scale 1:24,000, dated January 1. Tehachapi Renewable Transmission Project, 2009, Draft EIR/EIS, 3.7 Geology, Soils and Paleontology, dated February. United States Department of Agriculture (USDA), 2006, Natural Resources Conservation Service, Digital General Soil Map of U.S., dated July 5. United States Department of Agriculture (USDA), 2007a, Natural Resources Conservation Service, National Soil Survey Handbook, Title 430-VI. United States Department of Agriculture (USDA), 2007b, Natural Resources Conservation Service, Soil Survey Geographic (SSURGO) database for Kern County, California, Southeastern Part, CA 670, dated December 10. United States Department of Agriculture (USDA), 2008a, Natural Resources Conservation Service, Soil Survey Geographic (SSURGO) database for Antelope Valley area, CA675, California, dated January 3.

ANA 032-063 (PER-02) LADWP (MARCH 2011) MS 115244 93 POWER ENGINEERS, INC. BARREN RIDGE RENEWABLE TRANSMISSION PROJECT—PRELIMINARY GEOTECHNICAL EVALUATION United States Department of Agriculture (USDA), 2008b, Natural Resources Conservation Service, Soil Survey Geographic (SSURGO) database for Los Angeles County, California, West San Fernando Valley area, CA 676, dated January 3. United States Department of Agriculture (USDA), 2008c, Natural Resources Conservation Service, Soil Survey Geographic (SSURGO) database for Angeles National Forest area, CA776, California, dated January 8. United States Department of Agriculture (USDA), 2008d, Web Soil Survey, http://websoilsurvey.nrcs.usda.gov/app/HomePage.htm. United States Geological Survey, 1952a (Photorevised 1988), Newhall, California Quadrangle Map, 7.5 Minute Series: Scale 1:24,000. United States Geological Survey, 1952b (Photorevised 1988), Val Verde, California Quadrangle Map, 7.5 Minute Series: Scale 1:24,000. United States Geological Survey, 1957 (Photorevised 1974), Lake Hughes, California Quadrangle Map, 7.5 Minute Series: Scale 1:24,000. United States Geological Survey, 1958a (Photorevised 1974), Del Sur, California Quadrangle Map, 7.5 Minute Series: Scale 1:24,000. United States Geological Survey, 1958b (Photorevised 1974), Green Valley, California Quadrangle Map, 7.5 Minute Series: Scale 1:24,000. United States Geological Survey, 1958c (Photorevised 1974), Lancaster West, California Quadrangle Map, 7.5 Minute Series: Scale 1:24,000. United States Geological Survey, 1958d (Photorevised 1974), Ritter Ridge, California Quadrangle Map, 7.5 Minute Series: Scale 1:24,000. United States Geological Survey, 1958e (Photorevised 1974), Sleepy Valley, California Quadrangle Map, 7.5 Minute Series: Scale 1:24,000. United States Geological Survey, 1958f (Photorevised 1988), Warm Springs, California Quadrangle Map, 7.5 Minute Series: Scale 1:24,000. United States Geological Survey, 1958g (Photorevised 1988), Whitaker Peak, California Quadrangle Map, 7.5 Minute Series: Scale 1:24,000. United States Geological Survey, 1960a (Photorevised 1988), Agua Dulce, California Quadrangle Map, 7.5 Minute Series: Scale 1:24,000. United States Geological Survey, 1960b (Photorevised 1988), Mint Canyon, California Quadrangle Map, 7.5 Minute Series: Scale 1:24,000. United States Geological Survey, 1966 (Photorevised 1988), San Fernando, California Quadrangle Map, 7.5 Minute Series: Scale 1:24,000. United States Geological Survey, 1973, Rosamond, California Quadrangle Map, 7.5 Minute Series: Scale 1:24,000. United States Geological Survey, 1991, Lebec, California Quadrangle Map, 7.5 Minute Series: Scale 1:24,000. United States Geological Survey, 1997 (2002rev), National Seismic Hazard Mapping Project, http://geohazards.cr.usgs.gov.eq. United States Geological Survey, 2008, Earthquake Ground Motion Parameter Java Application, Java Ground Motion Parameter Calculator – Version 5.0.8; http://earthquake.usgs.gov/ research/hazmaps/design/.

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10.0 ACRONYMS AND ABBREVIATIONS

ANF Angeles National Forest BLM United States Department of the Interior, Bureau of Land Management BMPs Best Management Practices BR-RIN Barren Ridge – Rinaldi Transmission Line BRRTP Barren Ridge Renewable Transmission Project CBC California Building Code CDMG California Division of Mines & Geology CDWR California Department of Water Resources CEQA California Environmental Quality Act CGS California Geological Survey COM Plan Construction, Operation and Maintenance Plan EIR Environmental Impact Report EIS Environmental Impact Statement g Acceleration Due to Gravity GIS Geographic Information Systems LADWP Los Angeles Department of Water & Power MCE Maximum Considered Earthquake Mmax Maximum Moment Magnitude MSL Mean Sea Level NEPA National Environmental Protection Act NFS National Forest Service NRCS National Resource Conservation Service PDCI Pacific Direct Current Intertie PGA Peak Ground Acceleration POD Plan of Development ROW Right of Way SCE Southern California Edison SCEC Southern California Earthquake Center SWPPP Storm Water Pollution Prevention Plan TRTP Tehachapi Renewable Transmission Project TSP Tubular Steel Poles USDA United States Department of Agriculture USFS United States Forest Service USGS United States Geological Survey

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