Natural Resource Damage Assessment Plan for the Tittabawassee River System Assessment Area Prepared under contract for: Remediation and Redevelopment Division Michigan Department of Environmental Quality PO Box 30426 Lansing, MI 48909 Contact: Judith Gapp Natural Resource Damage Assessment Plan for the Tittabawassee River System Assessment Area Prepared under contract for: Remediation and Redevelopment Division Michigan Department of Environmental Quality PO Box 30426 Lansing, MI 48909 Contact: Judith Gapp Prepared by: Stratus Consulting Inc. PO Box 4059 Boulder, CO 80306-4059 303-381-8000 1920 L St. NW, Ste. 420 Washington, DC 20036 Contacts: Kaylene Ritter P. David Allen II April 2008 SC11317 Contents List of Figures............................................................................................................................ vii List of Tables ...............................................................................................................................ix List of Acronyms and Abbreviations ........................................................................................xi Chapter 1 Introduction...................................................................................................... 1-1 1.1 Statement of Purpose ......................................................................................... 1-1 1.2 Trusteeship Authority........................................................................................ 1-2 1.2.1 State trustees.......................................................................................... 1-2 1.2.2 Federal trustees...................................................................................... 1-2 1.2.3 Tribal trustees........................................................................................ 1-3 1.3 Decision to Perform a Type B Assessment........................................................ 1-3 1.4 Natural Resource Damage Assessment Process ................................................ 1-4 1.4.1 Preassessment phase.............................................................................. 1-4 1.4.2 Assessment plan phase........................................................................... 1-5 1.4.3 Assessment phase...................................................................................1-5 1.4.4 Post-assessment phase........................................................................... 1-6 1.5 Natural Resource Damage Coordination with Response Actions ..................... 1-6 1.6 Public Review and Comment............................................................................. 1-7 1.7 Organization of the Assessment Plan ................................................................ 1-8 Chapter 2 Description of the Assessment Area............................................................... 2-1 2.1 River System...................................................................................................... 2-1 2.1.1 Tittabawassee River location, geomorphology, hydrology, and anthropogenic influences ....................................................................... 2-1 2.1.2 Saginaw River location, geomorphology, and anthropogenic influences ....................................................................... 2-4 2.1.3 Saginaw Bay.......................................................................................... 2-6 2.2 Aerial Deposition Area Associated with the Dow Plant.................................... 2-7 2.3 Dow Midland Plant Property ............................................................................. 2-7 2.4 TRSAA Biota..................................................................................................... 2-9 2.4.1 Aquatic biota.......................................................................................... 2-9 2.4.2 TRSAA terrestrial and wetland biota................................................... 2-12 2.4.3 Threatened and endangered species..................................................... 2-14 SC11317 Contents (April 2008) Chapter 3 Hazardous Substances Released by Dow....................................................... 3-1 3.1 Operational History of the Dow Midland Plant................................................. 3-1 3.1.1 Early sources of dioxins and furans: electrolytic production of chlorine using carbon electrodes............................................................ 3-4 3.1.2 Later sources of dioxins and furans: electrolytic production of chlorophenols......................................................................................... 3-5 3.1.3 Dioxins and furans produced by incineration practices......................... 3-5 3.1.4 Dow waste management history ............................................................ 3-6 3.2 Remedial Actions and Risk Assessments in the TRSAA .................................. 3-9 3.2.1 Historical remedial investigations (1980s-1990s) ................................. 3-9 3.2.2 Removal actions................................................................................... 3-16 3.2.3 Ecological risk assessments................................................................. 3-17 Chapter 4 Confirmation of Exposure............................................................................... 4-1 4.1 Study Area Advisories ....................................................................................... 4-1 4.1.1 Fish consumption advisories.................................................................. 4-2 4.1.2 Wild game advisories............................................................................. 4-4 4.1.3 Soil advisories........................................................................................ 4-5 4.2 Other Data Confirming Exposure of Natural Resources ................................... 4-7 4.3 Surface Water and Sediment Resources ............................................................ 4-7 4.3.1 Definition ............................................................................................... 4-7 4.3.2 Exposed surface water and sediment resources..................................... 4-7 4.4 Biological Resources......................................................................................... 4-8 4.4.1 Definition ............................................................................................... 4-8 4.4.2 Exposed biological resources................................................................. 4-8 4.5 Groundwater Resources..................................................................................... 4-8 4.5.1 Definition ............................................................................................... 4-8 4.5.2 Exposed groundwater resources ............................................................ 4-9 4.6 Geologic Resources........................................................................................... 4-9 4.6.1 Definition ............................................................................................... 4-9 4.6.2 Exposed geologic resources................................................................... 4-9 Chapter 5 Assessment Approach...................................................................................... 5-1 5.1 Overall Approach............................................................................................... 5-1 5.1.1 Iterative assessment planning and assessment determination................ 5-2 5.1.2 Cooperative assessment with Dow ........................................................ 5-2 5.2 Injury and Pathway Determination.................................................................... 5-3 5.2.1 Definitions of injury............................................................................... 5-3 5.2.2 Injury determination approaches ........................................................... 5-5 5.2.3 Pathway determination approach........................................................... 5-5 5.2.4 Quantification of spatial and temporal extent of injuries .................... 5-10 Page iv SC11317 Contents (April 2008) 5.2.5 Determination of baseline.................................................................... 5-11 5.2.6 Estimation of losses ............................................................................. 5-11 5.2.7 Estimation of recovery to baseline....................................................... 5-11 5.3 Determining Restoration Opportunities and Benefits...................................... 5-11 5.3.1 Categories of evaluation criteria.......................................................... 5-12 5.3.2 Evaluation criteria and their interpretation.......................................... 5-12 5.3.3 Restoration opportunities..................................................................... 5-15 5.4 Scaling Restoration Gains to Losses Caused by Injuries................................. 5-15 5.5 Development of the Restoration and Compensation Determination Plan ....... 5-17 5.6 New TRSAA-Specific Assessment Studies Being Considered by the Trustees ...................................................................................................... 5-17 5.6.1 Restoration planning............................................................................ 5-18 5.6.2 Biological and ecological injuries........................................................ 5-18 5.6.3 Analysis of past injuries and future trajectories of injuries ................. 5-19