June 2011 BARREN RIDGE RENEWABLE TRANSMISSION PROJECT Water Resources and Hydrology Supplemental Technical Report PROJECT NUMBER: 122708 PROJECT CONTACT: ALLISON CARVER EMAIL: [email protected] PHONE: 714-507-2700 POWER ENGINEERS, INC. BRRTP – WATER RESOURCES AND HYDROLOGY SUPPLEMENTAL TECHNICAL REPORT FOR THE ANF Water Resources and Hydrology Supplemental Technical Report for the Angeles National Forest PREPARED FOR: LOS ANGELES DEPARTMENT OF WATER AND POWER 111 NORTH HOPE STREET LOS ANGELES CA 90012 PREPARED BY: POWER ENGINEERS, INC. (714) 507-2700 WWW.POWERENG.COM ALLISON CARVER WATER RESOURCES (714) 507-2705 MICHEL YBARRONDO, P.E. (HYDROLOGY) (208) 288-6131 ANA 119-150 (PER-02) 122708 (JUNE 2011) AC POWER ENGINEERS, INC. BRRTP – WATER RESOURCES AND HYDROLOGY SUPPLEMENTAL TECHNICAL REPORT FOR THE ANF TABLE OF CONTENTS 1.0 INTRODUCTION ............................................................................................................................ 1 2.0 PURPOSE AND SCOPE .................................................................................................................. 2 2.1 Issues ............................................................................................................................................. 2 3.0 BACKGROUND .............................................................................................................................. 3 3.1 General Description ...................................................................................................................... 3 4.0 AFFECTED ENVIRONMENT ........................................................................................................ 7 4.1 Water Resource Inventory .......................................................................................................... 10 4.2 Watersheds .................................................................................................................................. 10 4.2.1. Liebre Gulch-Piru Creek Watershed (HUC 180701020509) .............................................. 10 4.2.2. Upper Castaic Creek Watershed (HUC 180701020303) .................................................... 11 4.2.3. Fish Creek-Piru Creek Watershed (HUC 180701020602) .................................................. 11 4.2.4. Lake Piru-Piru Creek Watershed (HUC 180701020603) ................................................... 12 4.2.5. Lower Castaic Creek Watershed (HUC 180701020306) .................................................... 13 4.2.6. San Francisquito Canyon Watershed (HUC 180701020402) ............................................. 13 4.2.7. Lower Bouquet Canyon Watershed (HUC 180701020202) ............................................... 14 4.2.8. Elizabeth Lake Watershed (HUC 180701020301) ............................................................. 15 4.2.9. Elizabeth Lake Canyon Watershed (HUC 180701020304) ................................................ 15 4.2.10. Agua Dulce Canyon Watershed (HUC 180701020104) ..................................................... 16 4.2.11. Mint Canyon Watershed (HUC 180701020106) ................................................................ 17 4.2.12. Upper Bouquet Canyon Watershed (HUC 180701020201) ................................................ 17 5.0 GUIDING LAWS, REGULATIONS, POLICIES, AND DIRECTION ......................................... 19 6.0 MANAGEMENT OBJECTIVES (DESIRED CONDITIONS) ..................................................... 21 7.0 IMPACT ASSESSMENT METHODOLOGY ............................................................................... 22 7.1 Impact Model .............................................................................................................................. 22 7.1.1. RUSLE Analysis ................................................................................................................. 22 7.1.2. Hydrologic Modeling .......................................................................................................... 22 7.2 Resource Sensitivity .................................................................................................................... 23 7.2.1. Sensitivity Values ............................................................................................................... 23 7.2.2. Access Levels and Ground Disturbance ............................................................................. 24 7.3 Impact Levels .............................................................................................................................. 24 7.4 Impact Assessment Methodology by Project Component .......................................................... 25 7.4.1. 230 kV Transmission Line .................................................................................................. 25 7.4.2. New 230 kV Circuit ............................................................................................................ 25 7.4.3. Reconductoring ................................................................................................................... 26 7.4.4. New Haskell Canyon Switching Station ............................................................................. 26 7.4.5. Expansion of Barren Ridge Switching Station .................................................................... 26 7.5 Impacts and Mitigation Planning ................................................................................................ 26 7.5.1. Types of Impacts ................................................................................................................. 37 8.0 IMPACT RESULTS ....................................................................................................................... 40 8.1 Alternative 1 ................................................................................................................................ 40 8.2 Alternative 2 ................................................................................................................................ 40 8.3 Alternative 2a .............................................................................................................................. 41 8.4 Alternative 3 ................................................................................................................................ 42 8.5 No Action Alternative ................................................................................................................. 42 9.0 CUMULATIVE WATERSHED EFFECTS ................................................................................... 43 9.1 Introduction ................................................................................................................................. 43 ANA 119-150 (PER-02) 122708 (JUNE 2011) AC i POWER ENGINEERS, INC. BRRTP – WATER RESOURCES AND HYDROLOGY SUPPLEMENTAL TECHNICAL REPORT FOR THE ANF 9.2 Impact Area ................................................................................................................................. 43 9.3 Present and Reasonably Foreseeable Actions ............................................................................. 43 9.3.1. Transmission Projects ......................................................................................................... 43 9.3.2. Transportation and Public Facilities.................................................................................... 44 9.3.3. Maintenance and Landscape Management Projects............................................................ 44 9.3.4. Local Projects ...................................................................................................................... 45 9.4 Cumulative Effects Analysis ....................................................................................................... 45 9.4.1. Direct and Indirect Effects Summary .................................................................................. 45 9.4.2. Cumulative Effects Evaluation ........................................................................................... 46 10.0 REFERENCES ............................................................................................................................... 47 APPENDIX A: RUSLE ANALYSIS ......................................................................................................... 48 APPENDIX B: STUDIED WATERSHED MAPS .................................................................................... 49 APPENDIX C: ASSUMPTIONS AND RESULTS ................................................................................... 50 TABLES Table 1. Watersheds in the BRRTP Area. .................................................................................................... 7 Table 2. Condition Categories for Watersheds in the USFS Pacific Southwest Region............................... 8 Table 3. Water Resources Impacts by Access Level Category ................................................................... 24 Table 4. General Practices .......................................................................................................................... 28 Table 5. Specifically Recommended Mitigation Measures ........................................................................ 31 ANA 119-150 (PER-02) 122708 (JUNE 2011) AC ii POWER ENGINEERS, INC. BRRTP – WATER RESOURCES AND HYDROLOGY SUPPLEMENTAL TECHNICAL REPORT FOR THE ANF 1.0 INTRODUCTION The City of Los Angeles Department