Final Record of Decision June 2020 Fort Riley Military Munitions Response Program Camp Forsyth Landfill Area 2 Munitions Response Site Operable Unit 09, FTRI-003-R-01 Geary County, Kansas U.S. Army Corps of Engineers Omaha District FORT RILEY Final Contract No.: W912DQ-17-D-3023 Delivery Order No.: W9128F-17-F-0233 Record of Decision MILITARY MUNITIONS RESPONSE PROGRAM FORT RILEY CAMP FORSYTH LANDFILL AREA 2 MUNITIONS RESPONSE SITE OPERABLE UNIT 09, FTRI-003-R-01 GEARY COUNTY, KANSAS Prepared for and Prepared by U.S. ARMY CORPS OF ENGINEERS Omaha District June 2020 Revision 01 Record of Decision Camp Forsyth Landfill Area 2 MRS, Fort Riley, Kansas Table of Contents 1.0 DECLARATION .......................................................................................................... 1-1 1.1 Site Name and Location.................................................................................................... 1-1 1.2 Statement of Basis and Purpose...................................................................................... 1-1 1.3 Assessment of Site ............................................................................................................ 1-1 1.4 Description of Selected Remedy ...................................................................................... 1-1 1.5 Statutory Determinations .................................................................................................. 1-1 1.5.1 Part 1: Statutory Requirements ................................................................................. 1-2 1.5.2 Part 2: Statutory Preference for Treatment .............................................................. 1-2 1.5.3 Part 3: Five-Year Review Requirement .................................................................... 1-2 1.6 ROD Data Certification Checklist ..................................................................................... 1-2 1.7 Authorizing Signatures ...................................................................................................... 1-3 2.0 DECISION SUMMARY ................................................................................................ 2-1 2.1 Site Name, Location, and Brief Description .................................................................... 2-1 2.2 Site History and Enforcement Activities .......................................................................... 2-1 2.2.1 Installation Mission and Operational History ............................................................ 2-2 2.2.2 History of Historical Maneuver and Training Areas ................................................. 2-3 2.2.3 Investigation Activities ................................................................................................ 2-4 2.3 Community Participation ................................................................................................. 2-15 2.4 Scope and Role of the Operable Unit or Response Action ......................................... 2-17 2.5 Site Characteristics ......................................................................................................... 2-18 2.5.1 Physical Profile.......................................................................................................... 2-18 2.5.2 Ecological and Cultural Resources Profile ............................................................. 2-20 2.5.3 Release Profile .......................................................................................................... 2-22 2.6 Current and Potential Future Land Use and Resource Uses ...................................... 2-23 2.7 Summary of Site Risks .................................................................................................... 2-24 2.7.1 Summary of MEC Risks ........................................................................................... 2-24 2.7.2 MC Risk Assessment ............................................................................................... 2-26 2.7.3 Basis for Taking Action............................................................................................. 2-26 2.8 Remedial Action Objectives ............................................................................................ 2-26 2.9 Description of Alternatives .............................................................................................. 2-26 2.9.1 Alternative 1: No Action ............................................................................................ 2-27 2.9.2 Alternative 2: LUCs ................................................................................................... 2-27 2.9.3 Alternative 3: Surface and Subsurface Removal of Military Munitions in Breakneck Creek and LUCs ....................................................................................................... 2-30 2.9.4 Alternative 4: MEC Removal for the Republican River and Breakneck Creek and LUCs .......................................................................................................................... 2-32 2.9.5 Alternative 5: Surface and Subsurface Removal of Military Munitions to Support Unlimited Use/Unrestricted Exposure (UU/UE) – Initial Screening Assessment Only .................................................................................................................................... 2-33 2.10 Comparative Analysis of Alternatives ............................................................................ 2-33 2.10.1 Overall Protection of Human Health and the Environment ................................... 2-36 2.10.2 Compliance with ARARs .......................................................................................... 2-36 2.10.3 Long-Term Effectiveness and Permanence ........................................................... 2-38 2.10.4 Reduction in Toxicity, Mobility, or Volume through Treatment ............................. 2-38 2.10.5 Short-Term Effectiveness......................................................................................... 2-38 June 2020 i Revision 01 Record of Decision Camp Forsyth Landfill Area 2 MRS, Fort Riley, Kansas 2.10.6 Implementability ........................................................................................................ 2-38 2.10.7 Cost ............................................................................................................................ 2-39 2.10.8 State Acceptance ...................................................................................................... 2-39 2.10.9 Community Acceptance ........................................................................................... 2-39 2.11 Principal Threat Wastes .................................................................................................. 2-39 2.12 Selected Remedy ............................................................................................................ 2-39 2.12.1 Summary of the Rationale for the Selected Remedy ............................................ 2-40 2.12.2 Description of the Selected Remedy ....................................................................... 2-40 2.12.3 Summary of Estimated Remedy Costs ................................................................... 2-40 2.12.4 Expected Outcomes of Selected Remedy .............................................................. 2-41 2.13 Statutory Determinations ................................................................................................ 2-42 2.13.1 Protection of Human Health and the Environment ................................................ 2-42 2.13.2 Compliance with ARARs .......................................................................................... 2-42 2.13.3 Cost Effectiveness .................................................................................................... 2-42 2.13.4 Utilization of Permanent Solutions and Alternative Treatment Technologies to the Maximum Extent Practicable ................................................................................... 2-43 2.13.5 Preference for Treatment as a Principal Element .................................................. 2-43 2.13.6 Five-Year Review Requirements ............................................................................. 2-43 2.14 Documentation of Significant Changes ......................................................................... 2-43 3.0 RESPONSIVENESS SUMMARY ................................................................................ 3-1 3.1 Stakeholder Comments and Lead Agency Responses ................................................. 3-1 3.2 Community Participation ................................................................................................... 3-1 3.3 Summary of Comments Received during the Public Comment Period and Agency Responses ......................................................................................................................... 3-1 3.3.1 Comments Received During the Public Meeting ..................................................... 3-1 3.3.2 Written Comments Received During the Comment Period ..................................... 3-1 3.4 Technical and Legal Issues .............................................................................................. 3-1 4.0 REFERENCES ............................................................................................................ 4-1 June 2020 ii Revision 01 Record of Decision Camp Forsyth Landfill Area