LITTLE SNAKE RIVER RESTORATION PROJECT DRAFT LITTLE SNAKE RIVER RESTORATION PROJECT DRAFT ENVIRONMENTAL

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  • LITTLE SNAKE RIVER RESTORATION PROJECT

    DRAFT ENVIRONMENTAL ASSESSMENT

    June 2013

  • Environmental Assessment Little Snake River Restoration Project

    TOC-1

    TABLE OF CONTENTS

    1. Introduction............................................................................................................................................ 1

    1.1 Document Format ........................................................................................................................... 1

    1.2 Purpose of Action ........................................................................................................................... 3

    1.3 Need for Action .............................................................................................................................. 3

    1.4 Decision Framework ....................................................................................................................... 4

    1.5 Scoping Process .............................................................................................................................. 4

    2. Alternatives ............................................................................................................................................ 4

    2.1 Alternative 1 – No Action Alternative ............................................................................................ 5

    2.2 Alternative 2 – Proposed Action..................................................................................................... 5

    2.3 Resource Protection Measures ...................................................................................................... 10

    2.3.1 Agriculture ....................................................................................................................... 10

    2.3.2 Cultural Resources ........................................................................................................... 10

    2.3.3 Water Resources .............................................................................................................. 10

    2.3.4 Infrastructure ................................................................................................................... 10

    2.3.5 Socioeconomic Resources ............................................................................................... 10

    2.3.6 Vegetation ........................................................................................................................ 10

    2.3.7 Invasive Plant Species ..................................................................................................... 10

    2.3.8 Wildlife Resources .......................................................................................................... 11

    2.3.9 Federally Listed Threatened and Endangered Species .................................................... 11

    2.3.10 Aquatic Resources ........................................................................................................... 11

    2.4 Alternatives Considered but Dismissed from Further Consideration ........................................... 11

    2.4.1 Use Riprap to Stabilize Channel ...................................................................................... 11

    2.5 Comparison of Alternatives .......................................................................................................... 12

    3. Affected Environment and Environmental Consequences .............................................................. 13

    3.1 Agriculture .................................................................................................................................... 13

    3.1.1 Alternative 1 – No Action ............................................................................................... 14

    3.1.2 Alternative 2 – Proposed Action ..................................................................................... 14

    3.2 Cultural Resources ........................................................................................................................ 15

    3.2.1 Class I Inventory .............................................................................................................. 15

    3.2.1.1 Alternative 1 – No Action ................................................................................ 17

    3.2.1.2 Alternative 2 – Proposed Action ...................................................................... 17

    3.3 Water Resources ........................................................................................................................... 18

    3.3.1 Hydrology ........................................................................................................................ 18

    3.3.1.1 Alternative 1 – No Action ................................................................................ 21

    3.3.1.2 Alternative 2 – Proposed Action ...................................................................... 21

    3.3.2 River Corridor Function .................................................................................................. 21

    3.3.2.1 Alternative 1 – No Action ................................................................................ 23

  • Environmental Assessment Little Snake River Restoration Project

    TOC-2

    3.3.2.2 Alternative 2 – Proposed Action ...................................................................... 23

    3.4 Infrastructure ................................................................................................................................ 24

    3.4.1 Adams Ditch Diversion ................................................................................................... 24

    3.4.2 Baggs Ditch Diversion..................................................................................................... 25

    3.4.3 Ready Ditch Diversion .................................................................................................... 27

    3.4.4 Town of Baggs Water Infiltration Gallery....................................................................... 27

    3.4.5 State Highway 789 Bridge ............................................................................................... 27

    3.4.5.1 Alternative 1 – No Action ................................................................................ 28

    3.4.5.2 Alternative 2 – Proposed Action ...................................................................... 28

    3.5 Socioeconomic Resources ............................................................................................................ 29

    3.5.1 Alternative 1 – No Action ............................................................................................... 30

    3.5.2 Alternative 2 – Proposed Action ..................................................................................... 30

    3.6 Vegetation ..................................................................................................................................... 30

    3.6.1 Alternative 1 – No Action ............................................................................................... 31

    3.6.2 Alternative 2 – Proposed Action ..................................................................................... 31

    3.7 Invasive Plant Species .................................................................................................................. 31

    3.7.1 Alternative 1 – No Action ............................................................................................... 32

    3.7.2 Alternative 2 – Proposed Action ..................................................................................... 32

    3.8 Wildlife Resources ....................................................................................................................... 33

    3.8.1 Ungulates ......................................................................................................................... 33

    3.8.1.1 Alternative 1 – No Action ................................................................................ 33

    3.8.1.2 Alternative 2 – Proposed Action ...................................................................... 33

    3.8.2 Avian ............................................................................................................................... 33

    3.8.2.1 Alternative 1 – No Action ................................................................................ 34

    3.8.2.2 Alternative 2 – Proposed Action ...................................................................... 34

    3.8.3 Reptiles and Amphibians ................................................................................................. 35

    3.8.3.1 Alternative 1 – No Action ................................................................................ 35

    3.8.3.2 Alternative 2 – Proposed Action ...................................................................... 35

    3.9 Federally Listed Threatened and Endangered Species ................................................................. 36

    3.9.1 Black-footed Ferret (Endangered) ................................................................................... 36

    3.9.1.1 Alternative 1 – No Action .....................................................................