MAMMOTH PACIFIC I REPLACEMENT PROJECT DRAFT ENVIRONMENTAL IMPACT REPORT California Clearinghouse Number 2011022020 July 2011 CEQA Lead Agency: Mono County P.O. Box 2415 Mammoth Lakes, California 93546 MAMMOTH PACIFIC I REPLACEMENT PROJECT DRAFT ENVIRONMENTAL IMPACT REPORT California Clearinghouse Number 2011022020 July 2011 CEQA Lead Agency: Mono County P.O. Box 2415 Mammoth Lakes, California 93546 Project Applicant: Mammoth Pacific, L.P. P.O. Box 1584 Mammoth Lakes, California 93546 CEQA Consultants: CAJA Environmental Services, LLC and Environmental Management Associates, Inc. 588 Explorer Street Brea, California 92821 Mammoth Pacific I Replacement Project Draft EIR TABLE OF CONTENTS Page TABLE OF CONTENTS ...........................................................................................................................................II LIST OF FIGURES ............................................................................................................................................... VIII LIST OF TABLES .................................................................................................................................................... IX LIST OF APPENDICES ............................................................................................................................................ X ACRONYMS ............................................................................................................................................................. XI SUMMARY .................................................................................................................................................................. 1 SUMMARY OF THE PROPOSED PROJECT .................................................................................................... 1 SUMMARY OF THE PROJECT ALTERNATIVES .......................................................................................... 1 SUMMARY OF THE ASSESSMENT .................................................................................................................. 4 1 INTRODUCTION .......................................................................................................................................... 1-1 1.1 OVERVIEW OF THE PROPOSED PROJECT ..................................................................................... 1-1 1.2 OBJECTIVES OF THE PROPOSED PROJECT AND THE EIR ........................................................ 1-1 1.2.1 Mammoth Pacific, L.P. .................................................................................................................... 1-1 1.2.2 Mono County .................................................................................................................................... 1-2 1.3 CASA DIABLO GEOTHERMAL PROJECTS ...................................................................................... 1-3 1.4 RELATIONSHIP TO STATUTES, REGULATIONS AND OTHER PLANS ..................................... 1-4 1.4.1 County of Mono General Plan ........................................................................................................ 1-5 1.4.1 Town of Mammoth Lakes General Plan ........................................................................................ 1-5 1.4.2 Agency Required Permits ............................................................................................................... 1-7 1.5 CEQA DOCUMENT ................................................................................................................................. 1-7 1.5.1 Conformance with CEQA ............................................................................................................... 1-7 1.5.2 Public Scoping .................................................................................................................................. 1-7 1.5.3 Identified Issues and Concerns ....................................................................................................... 1-8 2 PROPOSED PROJECT AND ALTERNATIVES ...................................................................................... 2-1 2.1 PROPOSED PROJECT ............................................................................................................................ 2-1 2.1.1 Project Overview ............................................................................................................................. 2-1 Project Location and Access .......................................................................................................................................... 2-1 Project Design and Power Generation Technology ....................................................................................................... 2-1 M–1 Plant Startup, Transition and Operations .............................................................................................................. 2-2 2.1.2 Replacement Plant Construction and Commissioning ................................................................. 2-2 Site Access and Roads .................................................................................................................................................... 2-4 Grading and Surface Disturbance ................................................................................................................................. 2-4 Project Facilities ............................................................................................................................................................ 2-4 Transmission Interconnection ........................................................................................................................................ 2-7 Construction Work Force, Traffic and Schedule ............................................................................................................ 2-7 Construction Water and Wastes ................................................................................................................................... 2-12 2.1.3 Pipeline Route, Design and Construction .................................................................................... 2-13 2.1.4 Existing Plant Demolition and Site Restoration .......................................................................... 2-13 Demolition Work Force, Traffic and Schedule ............................................................................................................. 2-13 Decommissioning and Demolition Wastes ................................................................................................................... 2-15 2.1.5 Replacement Plant Operations and Maintenance ....................................................................... 2-15 Geothermal Fluid System ............................................................................................................................................. 2-15 Motive Fluid System ..................................................................................................................................................... 2-15 Cooling System ............................................................................................................................................................ 2-16 Operations Work Force, Traffic and Schedule ............................................................................................................. 2-17 Hazardous Materials ................................................................................................................................................... 2-17 Fire Prevention and Suppression ................................................................................................................................. 2-18 ii Mammoth Pacific I Replacement Project Draft EIR Operational Emissions ................................................................................................................................................. 2-19 Operational Discharges ............................................................................................................................................... 2-20 Operational Wastes ...................................................................................................................................................... 2-20 2.1.6 Interim Site Restoration and End of Project Site Reclamation ................................................. 2-21 2.1.7 Environmental Protection Measures Adopted by the Project ................................................... 2-21 Surface and Ground Water Quality Protection ............................................................................................................ 2-21 Air Quality Protection .................................................................................................................................................. 2-21 Prevention of Noise ...................................................................................................................................................... 2-22 Geotechnical and Geologic Hazards ........................................................................................................................... 2-22 Protection of Fish, Wildlife, and Botanical Resources ................................................................................................. 2-22 Protection of Cultural Resources ................................................................................................................................