SANTA SUSANA MOUNTAINS TRAILS MASTER PLAN – PHASE II INITIAL STUDY / MITIGATED NEGATIVE DECLARATION PREPARED FOR: COUNTY OF LOS ANGELES DEPARTMENT OF PARKS AND RECREATION 510 S. VERMONT AVE. LOS ANGELES, CA 90020 PREPARED BY: SAPPHOS ENVIRONMENTAL, INC. 430 NORTH HALSTEAD STREET PASADENA, CALIFORNIA 91107 NOVEMBER 2, 2017 Table of Contents SECTION PAGE 1. Project Description ........................................................................................................................................ 1-1 1.1 Project Title ....................................................................................................................................... 1-1 1.2 Lead Agency ...................................................................................................................................... 1-1 1.3 Primary Contact Person ................................................................................................................. 1-1 1.4 Project Location ............................................................................................................................... 1-1 1.5 Project Sponsor ................................................................................................................................ 1-2 1.6 General Plan Land Use Designation ............................................................................................. 1-3 1.7 Zoning ................................................................................................................................................ 1-5 1.8 Background and Existing Conditions ............................................................................................ 1-7 1.9 Project Description ........................................................................................................................ 1-13 1.10 Statement of Objectives ................................................................................................................ 1-16 1.11 Construction Scenario ................................................................................................................... 1-17 1.12 Operation and Maintenance ......................................................................................................... 1-20 1.12 Related Projects .............................................................................................................................. 1-21 2. Environmental Checklist and Impact Analysis .......................................................................................... 2-1 2.1 Aesthetics ........................................................................................................................................... 2-5 2.2 Agriculture/Forest ......................................................................................................................... 2-12 2.3 Air Quality ....................................................................................................................................... 2-16 2.4 Biological Resources ...................................................................................................................... 2-20 2.5 Cultural Resources .......................................................................................................................... 2-28 2.6 Energy ............................................................................................................................................. 2-33 2.7 Geology/Soils ................................................................................................................................. 2-35 2.8 Greenhouse Gas Emissions .......................................................................................................... 2-41 2.9 Hazards/Hazardous Materials ...................................................................................................... 2-43 2.10 Hydrology/Water Quality ............................................................................................................. 2-51 2.11 Land Use/Planning ........................................................................................................................ 2-58 2.12 Mineral Resources .......................................................................................................................... 2-61 2.13 Noise ................................................................................................................................................ 2-64 2.14 Population/Housing ...................................................................................................................... 2-68 2.15 Public Services ................................................................................................................................ 2-70 2.16 Recreation ........................................................................................................................................ 2-77 2.17 Transportation/Traffic .................................................................................................................. 2-83 2.18 Tribal Cultural Resources .............................................................................................................. 2-86 2.19 Utilities/Services ............................................................................................................................. 2-89 2.20 Mandatory Findings of Significance ............................................................................................ 2-94 3. Mitigation Measures ....................................................................................................................................... 3-1 4. Report Preparation ......................................................................................................................................... 4-1 5. References ....................................................................................................................................................... 5-1 i-1/3 TABLE PAGE 1.6-1 Project Study Area Land Use Designations ........................................................................................ 1-4 1.7-1 Proposed Project Area Zoning Designations ..................................................................................... 1-6 1.8-1 Los Angeles County Park Service Area Definitions ........................................................................ 1-10 1.8-2 Existing Trails within Project Study Area .......................................................................................... 1-12 1.9-1 County Trail Types ................................................................................................................................ 1-13 1.9-2 Proposed Trail Corridors ..................................................................................................................... 1-14 1.9-3 Proposed Facilities ................................................................................................................................ 1-16 1.11-1 Proposed Trail Corridor NWI Crossings .......................................................................................... 1-18 1.12-1 Trail Maintenance Activity Equipment .............................................................................................. 1-21 1.13-1 List of Related Projects ........................................................................................................................ 1-22 2.2-1 FMMP Important Farmland ................................................................................................................ 2-13 2.9-1 EnviroStor Data .................................................................................................................................... 2-45 2.9-2 Geotracker Data: Permitted Underground Storage Tanks [USTs] ................................................ 2-45 2.9-3 Geotracker Data: Hazardous Sites ...................................................................................................... 2-46 2.13-1 Ambient Noise Levels .......................................................................................................................................... 2-64 2.13-2 Construction Activity Noise Levels at 50 Feet ................................................................................. 2-66 2.13-3 Predicted Distance at Which Noise Impact Would Be below Level of Significance .................. 2-66 2.14-1 Unincorporated Los Angeles County Growth Forecast ................................................................. 2-68 2.16-1 Regional Parkland within Project Study Area ................................................................................... 2-78 2.16-2 Existing Local Parks within Service Areas of Project Study Area ................................................. 2-79 2.16-3 Public Access Open Space within One Mile of Project Study Area .............................................. 2-82 2.19-1 Proposed Trail Related Restroom Facilities ...................................................................................... 2-90 FIGURE FOLLOWS PAGE 1.4-1 Regional Vicinity Map ............................................................................................................................ 1-1 1.4-2 Local Vicinity Map .................................................................................................................................. 1-1 1.4-3 Topographic