Enbridge Line 6B MP 608 Releases Marshall, MI Evaluation of Potential Impact of Released Oil on Groundwater used for Drinking Water (Hydrogeological Evaluation Report) Prepared: October 30, 2010 Enbridge Line 6B MP 608 Release Marshall, MI Evaluation of Potential Impact of Released Oil on Groundwater used for Drinking Water (Hydrogeological Evaluation Report) Prepared October 30, 2010 Table of Contents 1.0 Introduction ........................................................................................................................................... 1 1.1 Background ............................................................................................................................. 1 1.2 Purpose and Overview ............................................................................................................ 2 1.3 Site Setting .............................................................................................................................. 2 1.4 Goals ....................................................................................................................................... 3 2.0 Historical Information on the Kalamazoo River ................................................................................. 5 2.1 Kalamazoo River .................................................................................................................... 5 2.2 Regional Geological Setting ................................................................................................... 6 2.3 Regional Hydrogeology ......................................................................................................... 8 2.4 United States Geological Survey Studies............................................................................... 9 3.0 Investigation Methods ........................................................................................................................ 11 3.1 Target Areas of Investigation ............................................................................................... 11 3.2 Point of Reference ................................................................................................................ 12 3.3 Residential Well Sampling ................................................................................................... 13 3.4 SAP and QAPP ..................................................................................................................... 16 3.5 Environmental Sites and Freedom of Information Act (FOIA) Search .............................. 16 3.6 Other Studies and Investigations .......................................................................................... 17 3.7 Evaluation of Production and Municipal Wells ................................................................... 25 3.8 Well-Head Protection ........................................................................................................... 27 4.0 Methods .............................................................................................................................................. 28 4.1 Drilling and Well Installation ............................................................................................... 28 4.2 Water Level Measurements .................................................................................................. 29 4.3 Slug-Testing .......................................................................................................................... 29 4.4 Water Sampling and Analysis .............................................................................................. 29 4.5 Data Validation ..................................................................................................................... 30 i 4.6 Deviations from Work Plan .................................................................................................. 31 5.0 Results ................................................................................................................................................. 32 5.1 Target Area 1 ........................................................................................................................ 32 5.1.1 Hydraulic Gradient ................................................................................................ 33 5.1.2 Presence of Crude Oil Constituents in Groundwater ............................................ 34 5.1.3 Major Cations / Anions ......................................................................................... 34 5.1.4 Summary ................................................................................................................ 36 5.2 Target Area 2 ........................................................................................................................ 37 5.2.1 Hydraulic Gradient ................................................................................................ 39 5.2.2 Presence of Crude Oil Constituents in Groundwater ............................................ 39 5.2.3 Major Cations / Anions ......................................................................................... 40 5.2.4 Summary ................................................................................................................ 41 5.3 Target Area 3 ........................................................................................................................ 41 5.3.1 Hydraulic Gradient ................................................................................................ 43 5.3.2 Presence of Crude Oil Constituents in Groundwater ............................................ 43 5.3.3 Major Cations / Anions ......................................................................................... 44 5.3.4 Summary ................................................................................................................ 45 5.4 Target Area 4 ........................................................................................................................ 45 5.4.1 Hydraulic Gradient ................................................................................................ 47 5.4.2 Presence of Crude Oil Constituents in Groundwater ............................................ 47 5.4.3 Major Cations / Anions ......................................................................................... 48 5.4.4 Summary ................................................................................................................ 49 5.5 Target Area 5 ........................................................................................................................ 49 5.5.1 Hydraulic Gradient ................................................................................................ 51 5.5.2 Presence of Crude Oil Constituents in Groundwater ............................................ 51 5.5.3 Major Cations / Anions ......................................................................................... 52 5.5.4 Summary ................................................................................................................ 53 5.6 Target Area 6 ........................................................................................................................ 53 5.6.1 Hydraulic Gradient ................................................................................................ 55 5.6.2 Presence of Crude Oil Constituents in Groundwater ............................................ 55 5.6.3 Major Cations / Anions ......................................................................................... 56 5.6.4 Summary ................................................................................................................ 57 ii 5.7 Target Area 7 ........................................................................................................................ 58 5.7.1 Hydraulic Gradient ................................................................................................ 59 5.7.2 Presence of Crude Oil Constituents in Groundwater ............................................ 59 5.7.3 Cations / Anions .................................................................................................... 60 5.7.4 Summary ................................................................................................................ 60 5.8 Target Area 8 ........................................................................................................................ 62 5.8.1 Hydraulic Gradient ................................................................................................ 63 5.8.2 Presence of Crude Oil Constituents in Groundwater ............................................ 63 5.8.3 Cations / Anions .................................................................................................... 64 5.8.4 Summary ................................................................................................................ 64 6.0 Discussion ........................................................................................................................................... 65 7.0 Recommendations .............................................................................................................................. 68 8.0 References ........................................................................................................................................... 69 iii List of Tables