I-90 Corridor Thin Environmental Assessment
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Baker-Snoqualmie National Forest I-90 Corridor Thin Environmental Assessment CHAPTER 1 - PURPOSE AND NEED ...................................................................................................................... 1 INTRODUCTION ........................................................................................................................................................... 1 BACKGROUND ............................................................................................................................................................ 1 PURPOSE AND NEED FOR ACTION ............................................................................................................................... 2 PROPOSED ACTION ..................................................................................................................................................... 3 DECISION FRAMEWORK .............................................................................................................................................. 6 RELATIONSHIP TO THE FOREST PLAN ......................................................................................................................... 6 Land Allocation..................................................................................................................................................... 6 Selected Forest Plan Standards and Guidelines ................................................................................................... 7 OTHER LAWS, DIRECTION, AND ANALYSES................................................................................................................ 9 SCOPING, PUBLIC INVOLVEMENT ............................................................................................................................. 12 ISSUES ...................................................................................................................................................................... 12 Significant Issues................................................................................................................................................. 12 CHAPTER 2 - ALTERNATIVES............................................................................................................................. 16 INTRODUCTION ......................................................................................................................................................... 16 ALTERNATIVES NOT CONSIDERED IN DETAIL........................................................................................................... 16 Treat Riparian Reserves Allocation to Address Current Habitat Conditions ..................................................... 16 Minimize Temporary Road Construction North of I-90...................................................................................... 16 Construct Only the Temporary Road Necessary to Permit More Economical Ground Based Yarding in Units 1, 2, 6, and 8............................................................................................................................................................ 18 Alternatives Considered in Detail....................................................................................................................... 19 Alternative 1–No Action...................................................................................................................................... 19 Alternative 2–Proposed Action ........................................................................................................................... 19 Best Management Practices, Constraints, and Mitigation Measures ................................................................. 21 Botany ................................................................................................................................................................. 21 Cultural............................................................................................................................................................... 22 Recreation........................................................................................................................................................... 22 Soils..................................................................................................................................................................... 23 Hydrology/Fisheries............................................................................................................................................ 23 Wildlife................................................................................................................................................................ 24 Fire, Fuels, and Air Quality................................................................................................................................ 24 Lands and Facilities............................................................................................................................................ 25 MONITORING ............................................................................................................................................................ 26 COMPARISON OF ALTERNATIVES.............................................................................................................................. 27 CHAPTER 3 - ENVIRONMENTAL EFFECTS ..................................................................................................... 28 FOREST VEGETATION ............................................................................................................................................... 28 Environmental Effects ......................................................................................................................................... 30 Cumulative Effects .............................................................................................................................................. 36 Forest Plan Consistency ..................................................................................................................................... 36 FIRE AND FUEL ......................................................................................................................................................... 37 Environmental Effects ......................................................................................................................................... 38 Cumulative Effects .............................................................................................................................................. 39 Forest Plan Consistency ..................................................................................................................................... 39 AIR QUALITY............................................................................................................................................................ 39 Environmental Effects ......................................................................................................................................... 40 Cumulative Effects .............................................................................................................................................. 40 Forest Plan Consistency ..................................................................................................................................... 40 ROADS AND TRANSPORTATION................................................................................................................................. 40 Environmental Effects ......................................................................................................................................... 41 Cumulative Effects .............................................................................................................................................. 44 Forest Plan Consistency ..................................................................................................................................... 45 SOILS ........................................................................................................................................................................ 45 i Mt. Baker-Snoqualmie National Forest I-90 Corridor Thin Environmental Assessment Environmental Effects ......................................................................................................................................... 46 Cumulative Effects .............................................................................................................................................. 47 Forest Plan Consistency ..................................................................................................................................... 48 HYDROLOGY............................................................................................................................................................. 48 Streams................................................................................................................................................................ 48 Stream Environmental Consequences................................................................................................................. 48 Flow Regime ......................................................................................................................................................