Southwest LRT Technical Memorandum No. 9 ENVIRONMENTAL EVALUATION DRAFT PRELIMINARY FOR REVIEW ONLY September 9, 2009 Southwest Transitway Contents 1.0 INTRODUCTION .................................................................................................. 1 2.0 SUMMARY OF ALTERNATIVES ......................................................................... 1 2.1 SEGMENT DESCRIPTIONS ............................................................................................ 2 2.1.1 Segment 1 ............................................................................................................. 2 2.1.2 Segment 3 ............................................................................................................. 2 2.1.3 Segment 4 ............................................................................................................. 3 2.1.4 Segment A ............................................................................................................. 3 2.1.5 Segments 3C-1 (Nicollet Mall) and 3C-2 (11th/12th Street) .................................... 4 3.0 RESOURCE ANALYSIS ...................................................................................... 5 3.1 CULTURAL RESOURCES ............................................................................................... 5 3.1.1 Legal and Regulatory Context ............................................................................... 5 3.1.2 Methodology .......................................................................................................... 6 3.1.3 Existing Conditions ................................................................................................ 8 3.1.4 Long-Term Effects ............................................................................................... 13 3.1.5 Short-Term Construction Effects ......................................................................... 17 3.1.6 Mitigation ............................................................................................................. 17 3.2 NATURAL RESOURCES ................................................................................................ 17 3.2.1 Legal and Regulatory Context ............................................................................. 18 3.2.2 Methodology ........................................................................................................ 18 3.2.3 Existing Conditions .............................................................................................. 19 3.2.4 Long-Term Effects ............................................................................................... 22 3.2.5 Short-Term Construction Effects ......................................................................... 22 3.2.6 Mitigation ............................................................................................................. 23 3.3 WATER RESOURCES ................................................................................................... 23 3.3.1 Legal and Regulatory Context ............................................................................. 23 3.3.2 Methodology ........................................................................................................ 27 3.3.3 Existing Conditions .............................................................................................. 29 3.3.4 Long-Term Effects ............................................................................................... 33 3.3.5 Short-Term Construction Effects ......................................................................... 35 3.3.6 Mitigation ............................................................................................................. 35 3.4 CONTAMINATED PROPERTIES AND HAZARDOUS MATERIALS .............................. 36 3.4.1 Preliminary Site Identification .............................................................................. 37 3.4.2 Impact Assessment Methodology........................................................................ 37 3.4.3 Long-Term Effects ............................................................................................... 39 3.4.4 Short-Term Construction Effects ......................................................................... 39 i Technical Memorandum 9 September 2009 Southwest Transitway 3.4.5 Mitigation ............................................................................................................. 41 3.5 SECTION 4(F) EVALUATION ......................................................................................... 42 3.5.1 Background Information and Regulatory Requirements ...................................... 42 3.5.2 Methodology ........................................................................................................ 44 3.5.3 Properties Protected by Section 4(f).................................................................... 45 3.5.4 Summary by Alternative ...................................................................................... 49 3.5.5 Avoidance Alternatives ........................................................................................ 49 3.5.6 Measures to Minimize Harm ................................................................................ 50 3.5.7 Coordination ........................................................................................................ 50 3.6 GEOLOGIC RESOURCES ............................................................................................. 50 3.6.1 Methodology ........................................................................................................ 51 3.6.2 Existing Conditions .............................................................................................. 53 3.6.3 Long-Term Effects ............................................................................................... 54 3.6.4 Short-Term Construction Effects ......................................................................... 54 3.6.5 Mitigation ............................................................................................................. 58 3.7 NOISE ............................................................................................................................. 58 3.7.1 Human Perception Levels ................................................................................... 58 3.7.2 Evaluation Criteria ............................................................................................... 60 3.7.3 Methodology ........................................................................................................ 60 3.7.4 Existing Conditions .............................................................................................. 61 3.7.5 Long-Term Effects ............................................................................................... 62 3.7.6 Short-Term Construction Effects ......................................................................... 62 3.7.7 Mitigation ............................................................................................................. 62 3.8 VIBRATION ..................................................................................................................... 62 3.8.1 Human Perception Levels ................................................................................... 62 3.8.2 Vibration Criteria .................................................................................................. 64 3.8.3 Methodology ........................................................................................................ 66 3.8.4 Existing Conditions .............................................................................................. 67 3.8.5 Long-Term Effects ............................................................................................... 67 3.8.6 Short-Term Construction Effects ......................................................................... 68 3.8.7 Mitigation ............................................................................................................. 68 4.0 EVALUATION MATRIX ..................................................................................... 69 ii September 2009 Technical Memorandum 9 Southwest Transitway List of Tables Table 1. Segments Associated with Alternatives .......................................................................................... 2 Table 2: Existing Historic Property within the Recommended APE of Segment A ....................................... 9 Table 3: Existing Historic Property within the Recommended APE of Segments C-1 and C-2 ................. 10 Table 4: Previously Known Archaeological Property within the Recommended APE of Segment 3 ........ 12 Table 5: Existing Historic Property within the Recommended APE of Segment 4 ..................................... 13 Table 6. Known Historic Properties by Alternative ...................................................................................... 13 Table 7. State or Federally Listed Species or Native Plant Communities within 1 Mile of Alignment 1A ................................................................................................................................. 20 Table 8. State or Federally Listed Species or Native Plant Communities within 1 Mile of Alignment 3A ................................................................................................................................. 21 Table 9.