Environmental Assessment United States Department of Pettit Lake Creek Weir Construction Agriculture Forest Service June 2020 Sawtooth National Recreation Area Sawtooth National Forest Blaine County, Idaho U.S. Department of Energy Bonneville Power Administration DOE/EA-2140 Section 31, T8N, R14 E, B.M. For information, contact: Kirk Flannigan Sawtooth National Recreation Area 5 North Fork Canyon Road Ketchum, Idaho 83340 (208) 727-5000 http://www.fs.fed.us/r4/sawtooth USDA FOREST SERVICE MISSION STATEMENT The mission of the USDA Forest Service is to sustain the health, diversity, and productivity of the Nation's forests and grasslands to meet the needs of present and future generation Table of Contents Purpose and Need ...................................................................................................................................................... 1 1.1 Introduction ........................................................................................................................................................................... 1 1.2 Need for Action ..................................................................................................................................................................... 1 1.3 Purpose .................................................................................................................................................................................... 2 1.4 Location .................................................................................................................................................................................... 3 1.5 Background ............................................................................................................................................................................. 4 1.5.1 Snake River Sockeye Salmon captive broodstock program ...................................................................... 4 1.5.2 Pettit Lake Creek Weir ............................................................................................................................................. 4 1.5.3 Shoshone Bannock Tribes of Fort Hall .............................................................................................................. 5 1.5.4 Sawtooth National Recreation Area.................................................................................................................... 6 1.5.5 Bonneville Power Administration ....................................................................................................................... 6 1.5.6 Columbia Basin Fish Accords and Extension .................................................................................................. 7 1.6 Decision Framework ........................................................................................................................................................... 7 1.7 Management Framework .................................................................................................................................................. 7 1.8 Public Involvement .............................................................................................................................................................. 7 Proposed Action and the No Action Alternative ............................................................................................ 8 2.1 Proposed Action ................................................................................................................................................................... 8 2.1.1 Project Design ............................................................................................................................................................ 10 2.1.2 Project Access and Staging Area ......................................................................................................................... 12 2.1.3 Project Layout ............................................................................................................................................................ 13 2.1.3.1 Sill (foundation of weir) .................................................................................................................................... 13 2.1.3.2 Bridge Weir ............................................................................................................................................................ 15 Smolt Collection Box Design .......................................................................................................................................... 16 Adult Collection/Picket Panel weir Design ............................................................................................................. 17 2.1.3.3 Trap Entrance, Water Intake, and Coarse Trash Rack ......................................................................... 18 2.1.4 Project Construction ............................................................................................................................................... 18 2.1.4.1 Construction Methodology .............................................................................................................................. 18 2.1.4.2 Instream Work Window ................................................................................................................................... 19 2.1.4.3 Construction Sequencing of Bridge Weir and Adult Holding Box ................................................... 20 2.1.4.4 Construction Equipment................................................................................................................................... 21 2.1.4.5 Hazardous Material Handling ......................................................................................................................... 21 2.1.5 Public Access and Safety ........................................................................................................................................ 21 2.1.6 Design Criteria ........................................................................................................................................................... 22 2.2 No Action Alternative ....................................................................................................................................................... 28 Pettit Lake Creek Weir Construction i 2.3 Other Alternatives Considered ..................................................................................................................................... 28 2.3.1 Addition of Mechanical Screen Cleaning to Existing Weir ....................................................................... 28 2.3.2 Screw Trap .................................................................................................................................................................. 28 2.3.3 Floating Inclined-Plane Trap ............................................................................................................................... 28 Affected Environment and Environmental Consequences...................................................................... 29 3.1 Short-term Direct Effects ................................................................................................................................................ 29 3.2 Long-term Anticipated Conditions ............................................................................................................................. 32 3.3 Vegetation ............................................................................................................................................................................. 33 3.3.1 Affected Environment ............................................................................................................................................. 33 3.3.2 Environmental Effects on Vegetation............................................................................................................... 35 3.4 Geology and Soils ............................................................................................................................................................... 36 3.4.1 Affected Environment ............................................................................................................................................. 36 3.4.2 Environmental Effects on Geology and Soils ................................................................................................. 36 3.5 Water ....................................................................................................................................................................................... 36 3.5.1 Affected Environment ............................................................................................................................................. 36 3.5.2 Environmental Effects on Water ........................................................................................................................ 37 3.6 Wetlands and Floodplains .............................................................................................................................................. 38 3.6.1 Affected Environment ............................................................................................................................................. 38 3.6.2 Environmental Effects on Wetlands and Floodplains 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