Initial Study and Draft Mitigated Negative Declaration Supporting an Incidental Take Permit and Streambed Alteration Agreement for the PG&E Gas Line 107 Retirement and Line 131 Valve Replacement Project Prepared for California Department of Fish and Wildlife February 2017 CONTENTS Contents Acronyms and Abbreviations ..................................................................................................... vii 1. Project Overview ................................................................................................................ 1-1 Purpose ....................................................................................................................................................................... 1-1 1.1 Location and General Information ................................................................................................................... 1-1 2. Project Description ............................................................................................................. 2-1 2.1 Proposed L-107 Retirement Work Activities .................................................................................................... 2-1 2.1.1 Potholing and Excavation ................................................................................................................... 2-3 2.1.2 Pipeline Cleaning ................................................................................................................................ 2-4 2.1.3 Underground Segment Retirement.................................................................................................... 2-4 2.1.4 Aboveground Segment Retirement ................................................................................................... 2-4 2.2 Proposed L-131 Valve Replacement Work Activities...................................................................................... 2-19 2.2.1 Vallecitos Road Location (Work Area 63) ......................................................................................... 2-19 2.2.2 Sheridan Road Location (Work Area 62) .......................................................................................... 2-19 2.3 Work Area Restoration ................................................................................................................................... 2-20 2.4 Schedule ......................................................................................................................................................... 2-20 2.5 Construction Management and Equipment ................................................................................................... 2-20 2.6 Applicant-proposed Measures ....................................................................................................................... 2-21 2.7 Land Uses and Setting Context ....................................................................................................................... 2-21 2.8 Relationship to Local Plans ............................................................................................................................. 2-21 3. Initial Study Checklist and Environmental Analysis .............................................................. 3-1 3.1 Aesthetics ......................................................................................................................................................... 3-1 3.1.1 Introduction ....................................................................................................................................... 3-1 3.1.2 Regulatory Setting .............................................................................................................................. 3-1 3.1.3 Environmental Setting ........................................................................................................................ 3-1 3.1.4 Impacts ............................................................................................................................................... 3-2 3.2 Agriculture and Forestry Resources ................................................................................................................. 3-3 3.2.1 Introduction ....................................................................................................................................... 3-3 3.2.2 Regulatory Setting .............................................................................................................................. 3-3 3.2.3 Environmental Setting ........................................................................................................................ 3-4 3.2.4 Applicant-proposed Measures ........................................................................................................... 3-4 3.2.5 Impacts ............................................................................................................................................... 3-5 3.3 Air Quality and Greenhouse Gases ................................................................................................................... 3-7 3.3.1 Introduction ....................................................................................................................................... 3-7 3.3.2 Regulatory Setting .............................................................................................................................. 3-8 3.3.3 Environmental Setting ...................................................................................................................... 3-11 3.3.4 Applicant-proposed Measures ......................................................................................................... 3-13 3.3.5 Impacts ............................................................................................................................................. 3-14 3.4 Biological Resources ....................................................................................................................................... 3-19 3.4.1 Introduction ..................................................................................................................................... 3-19 3.4.2 Regulatory Setting ............................................................................................................................ 3-21 3.4.3 Environmental Setting ...................................................................................................................... 3-23 3.4.4 Applicant-proposed Measures ......................................................................................................... 3-46 3.4.5 Impacts ............................................................................................................................................. 3-50 3.5 Cultural Resources, Tribal Cultural Resources, and Paleontological Resources ............................................. 3-59 3.5.1 Introduction ..................................................................................................................................... 3-59 3.5.2 Regulatory Setting ............................................................................................................................ 3-60 3.5.3 Environmental Setting ...................................................................................................................... 3-62 iii CONTENTS 3.5.4 Applicant-proposed Measures ......................................................................................................... 3-65 3.5.5 Impacts ............................................................................................................................................. 3-66 3.6 Geology and Soils ........................................................................................................................................... 3-69 3.6.1 Introduction ..................................................................................................................................... 3-69 3.6.2 Regulatory Setting ............................................................................................................................ 3-69 3.6.3 Environmental Setting ...................................................................................................................... 3-70 3.6.4 Impacts ............................................................................................................................................. 3-72 3.7 Hazards and Hazardous Materials .................................................................................................................. 3-75 3.7.1 Introduction ..................................................................................................................................... 3-75 3.7.2 Environmental Setting ...................................................................................................................... 3-76 3.7.3 Applicant-proposed Measures ......................................................................................................... 3-76 3.7.4 Impacts ............................................................................................................................................. 3-77 3.8 Hydrology and Water Quality ......................................................................................................................... 3-81 3.8.1 Introduction ....................................................................................................................................