National Aeronautics and Space Administration Draft Supplemental Environmental Impact Statement for Soil Cleanup Activities at Santa Susana Field Laboratory Ventura County, California Prepared for National Aeronautics and Space Administration Santa Susana Field Laboratory Ventura County, California October 25, 2019 Draft SEIS Supplemental Environmental Impact Statement for Soil Cleanup Activities at Santa Susana Field Laboratory Prepared for National Aeronautics and Space Administration Santa Susana Field Laboratory Ventura County, California October 25, 2019 This page intentionally left blank. DRAFT Cover Sheet Draft Supplemental Environmental Impact Statement for Soil Cleanup Activities at Santa Susana Field Laboratory Lead Agency: National Aeronautics and Space Administration Point of Contact: Peter Zorba SSFL Project Director 5800 Woolsey Canyon Road Canoga Park, CA 91304 [email protected] Date: October 25, 2019 Abstract: The National Aeronautics and Space Administration (NASA) has prepared this Supplemental Environmental Impact Statement (SEIS) to inform NASA decision makers, regulating agencies, and the public about the environmental impacts of the proposed soil cleanup activities at NASA’s Santa Susana Field Laboratory (SSFL) in Ventura County, California. NASA has prepared this SEIS in accordance with the National Environmental Policy Act of 1969 (NEPA), as amended (42 United States Code 4321 et seq.); the NEPA- implementing regulations issued by the Council on Environmental Quality (CEQ) (Title 40 Code of Federal Regulations [CFR] Parts 1500–1508); and the NASA Procedural Requirements 8580.1 for implementing NEPA (14 CFR Part 1216, Subpart 1216.3). For NASA’s soil cleanup activities at SSFL, significant new information relevant to the scope of the soil cleanup and potential environmental impacts has been identified since the publication of NASA’s 2014 Environmental Impact Statement. Specifically, there has been a significant increase in the expected soil remediation area and volume as determined by the follow-on field work and verification by the California Department of Toxic Substances Control in its draft Programmatic Environmental Impact Report. Section 1, Purpose and Need, describes the site history, reasons for conducting this evaluation, and the scope of the analysis. Section 2, Description of Proposed Action Alternatives, describes the Action Alternatives for implementing the soil remediation and the No Action Alternative for soil cleanup. This section also includes a description of other alternatives and resource areas that were considered but removed from further consideration. Section 3, Affected Environment and Environmental Consequences, provides an overview of the existing physical, biological, social, and cultural conditions and the potential environmental impacts from the Proposed Action Alternatives on the NASA-administered property at SSFL. DRAFT This page intentionally left blank. DRAFT Contents Section Page Acronyms and Abbreviations .................................................................................................................. vii Executive Summary ............................................................................................................................. ES-1 1 Purpose and Need ..................................................................................................................... 1-1 1.1 Introduction ........................................................................................................................... 1-1 1.2 Site History and Description .................................................................................................. 1-7 1.3 Site Characterization and Remediation ................................................................................. 1-9 1.4 SSFL Administration and Commitments ................................................................................ 1-9 1.5 Purpose and Need for Action ............................................................................................... 1-10 1.6 Scope of the Analysis ........................................................................................................... 1-10 1.7 Decision to be Made ............................................................................................................ 1-10 2 Description of Proposed Action Alternatives .............................................................................. 2-1 2.1 Proposed Action ..................................................................................................................... 2-1 2.1.1 Soil Treatment Technologies .................................................................................... 2-1 2.2 Action Alternatives ................................................................................................................ 2-7 2.2.1 Alternative A: AOC Cleanup ...................................................................................... 2-8 2.2.2 Alternative B: Revised LUT Levels Cleanup ............................................................... 2-9 2.2.3 Alternative C: Suburban Residential Cleanup ......................................................... 2-10 2.2.4 Alternative D: Recreational Cleanup....................................................................... 2-11 2.2.5 Alternative Comparison .......................................................................................... 2-12 2.3 Alternatives and Options Eliminated ................................................................................... 2-23 2.3.1 Additional Risk-based Cleanup Alternatives ........................................................... 2-23 2.3.2 Additional Cleanup Technology Options ................................................................ 2-23 2.3.3 Additional Soil Transport Options ........................................................................... 2-24 2.4 Resources Eliminated from Further Consideration ............................................................. 2-25 3 Affected Environment and Environmental Consequences ........................................................... 3-1 3.1 Cultural Resources ................................................................................................................. 3-4 3.1.1 Affected Environment ............................................................................................... 3-7 3.1.2 Environmental Consequences ................................................................................ 3-10 3.1.3 Mitigation Measures ............................................................................................... 3-20 3.1.4 Summary of Impacts ............................................................................................... 3-21 3.2 Biological Resources ............................................................................................................ 3-22 3.2.1 Affected Environment ............................................................................................. 3-22 3.2.2 Environmental Consequences ................................................................................ 3-35 3.2.3 Best Management Practices and Mitigation Measures .......................................... 3-45 3.2.4 Summary of Impacts ............................................................................................... 3-46 3.3 Air Quality ............................................................................................................................ 3-47 3.3.1 Affected Environment ............................................................................................. 3-47 3.3.2 Environmental Consequences ................................................................................ 3-53 3.3.3 Best Management Practices and Mitigation Measures .......................................... 3-58 3.3.4 Summary of Impacts ............................................................................................... 3-59 3.4 Water Resources .................................................................................................................. 3-60 3.4.1 Affected Environment ............................................................................................. 3-60 3.4.2 Environmental Consequences ................................................................................ 3-65 AX0822181311COS DRAFT iii CONTENTS CONTINUED 3.4.3 Mitigation Measures ............................................................................................... 3-69 3.4.4 Summary of Impacts ............................................................................................... 3-69 3.5 Geology ................................................................................................................................ 3-71 3.5.1 Affected Environment ............................................................................................. 3-71 3.5.2 Environmental Consequences ................................................................................ 3-81 3.5.3 Best Management Practices ................................................................................... 3-84 3.5.4 Summary of Impacts ............................................................................................... 3-84 3.6 Hazardous and Nonhazardous Materials and Waste .......................................................... 3-85 3.6.1 Affected Environment ............................................................................................