DRAFT East Highline Reservoir and Intake Channel Project Environmental Impact Report Prepared by: Imperial Irrigation District 333 East Barioni Boulevard Imperial, California 92251 Contact: Justina Gamboa-Arce Prepared with assistance from: FEBRUARY 2020 TABLE OF CONTENTS Section Page No. EXECUTIVE SUMMARY ...................................................................................................... ES-1 ES.1 Document Purpose .............................................................................................. ES-1 ES.2 Project Location .................................................................................................. ES-1 ES.3 Project Description ............................................................................................... ES-2 ES.3.1 Project Background ............................................................................... ES-2 ES.3.2 Project Summary ................................................................................... ES-2 ES.3.3 Proposed Project Objectives ................................................................. ES-3 ES.3.4 Required Permits and/or Approval ....................................................... ES-3 ES.4 Summary of Environmental Impacts and Mitigation Measures........................... ES-4 ES.5 Areas of Controversy/Issues to Be Resolved ..................................................... ES-29 ES.6 Summary of Project Alternatives ....................................................................... ES-29 CHAPTER 1 INTRODUCTION .............................................................................................. 1-1 1.1 Project Location and Region of Influence ........................................................... 1-1 1.1.1 Lower Colorado River ............................................................................. 1-1 1.1.2 IID Water Service Area and All American Canal ................................... 1-2 1.2 Background .......................................................................................................... 1-3 1.2.1 Colorado River ......................................................................................... 1-3 1.2.2 Quantification Settlement Agreement...................................................... 1-3 1.3 CEQA/NEPA Documentation Related to the Project .......................................... 1-4 1.3.1 Water Conservation and Transfer Project and Habitat Conservation Plan EIR .................................................................................................................. 1-4 1.3.2 Program EIR for the Implementation of the Colorado River Quantification Settlement Agreement.................................................................. 1-4 1.3.3 AAC Surgace Water Seepage Water Recovery Project Draft MND ....... 1-5 1.4 Other Proposed Projects Related to Resources Affected by the Proposed Project ... .............................................................................................................................. 1-6 1.5 Project Approvals................................................................................................. 1-6 1.5.1 Federal...................................................................................................... 1-7 1.5.2 State.......................................................................................................... 1-7 1.5.3 Local ........................................................................................................ 1-8 1.6 Consultation and Coordination ............................................................................ 1-8 1.6.1 Agency Coordination and Consultation ................................................... 1-8 1.6.2 Public Scoping ......................................................................................... 1-9 1.7 Project Summary ................................................................................................ 1-10 1.8 Draft EIR Organization and Contents ................................................................ 1-10 East Highline Reservoir EIR February 2020 TOC-ii TABLE OF CONTENTS CHAPTER 2 ENVIRONMENTAL SETTING ....................................................................... 2-1 2.1 Location ............................................................................................................... 2-1 2.2 Existing Site Conditions ...................................................................................... 2-2 2.2.1 Vegetation and Land Covers .................................................................... 2-2 2.2.2 Hydrological Setting ................................................................................ 2-2 2.3 Surrounding Land Uses........................................................................................ 2-3 2.4 General Plan Designation and Zoning ................................................................. 2-4 CHAPTER 3 PROJECT DESCRIPTION............................................................................... 3-1 3.1 Introduction .......................................................................................................... 3-1 3.2 Project Purpose and Objectives ........................................................................... 3-1 3.3 Proposed Project .................................................................................................. 3-3 3.3.1 Location ................................................................................................... 3-3 3.3.2 Summary .................................................................................................. 3-4 3.3.3 Project Components ................................................................................. 3-6 3.3.4 Construction ............................................................................................. 3-9 3.3.5 Operation................................................................................................ 3-10 3.4 Alternatives ........................................................................................................ 3-11 3.4.1 Selection of Project Alternatives ........................................................... 3-11 3.4.2 Description of Alternatives .................................................................... 3-12 CHAPTER 4 ENVIRONMENTAL IMPACT CONSIDERATIONS ................................... 4-1 4.1 Aesthetics .......................................................................................................... 4.1-1 4.1.1 Existing Conditions ............................................................................... 4.1-1 4.1.2 Relevant Plans, Policies, and Ordinances ............................................. 4.1-2 4.1.3 Thresholds of Significance ................................................................... 4.1-4 4.1.4 Impacts Analysis ................................................................................... 4.1-5 4.1.5 Mitigation Measures ............................................................................. 4.1-8 4.1.6 Level of Significance After Mitigation ................................................. 4.1-8 4.2 Air Quality ........................................................................................................ 4.2-1 4.2.1 Existing Conditions ............................................................................... 4.2-1 4.2.2 Pollutants and Effects ........................................................................... 4.2-3 4.2.3 Relevant Plans, Policies, and Ordinances ............................................. 4.2-8 4.2.4 Thresholds of Significance ................................................................. 4.2-13 4.2.5 Impacts Analysis ................................................................................. 4.2-14 4.2.6 Mitigation Measures ........................................................................... 4.2-24 4.2.7 Level of Significance After Mitigation ............................................... 4.2-26 4.3 Biological Resources ........................................................................................ 4.3-1 4.3.1 Existing Conditions ............................................................................... 4.3-1 4.3.2 Relevant Plans, Policies, and Ordinances ........................................... 4.3-17 East Highline Reservoir EIR February 2020 TOC-iii TABLE OF CONTENTS 4.3.3 Thresholds of Significance ................................................................. 4.3-23 4.3.4 Impacts Analysis ................................................................................. 4.3-24 4.3.5 Mitigation Measures ........................................................................... 4.3-43 4.3.6 Level of Significance After Mitigation ............................................... 4.3-52 4.4 Cultural Resources ............................................................................................ 4.4-1 4.4.1 Existing Conditions ............................................................................... 4.4-1 4.4.2 Relevant Plans, Policies, and Ordinances ............................................. 4.4-9 4.4.3 Thresholds of Significance ................................................................. 4.4-21 4.4.4 Impacts Analysis ................................................................................. 4.4-21 4.4.5 Mitigation Measures ........................................................................... 4.4-29