Hyrum Dam Spillway Replacement Project Final Environmental Assessment PRO-EA-14-003 Cache County, Utah Provo Area Office Upper Colorado Region U.S. Department of the Interior Bureau of Reclamation Provo Area Office Provo, Utah August 2016 Mission Statements The mission of the Department of the Interior is to protect and manage the Nation’s natural resources and cultural heritage; provide scientific and other information about those resources; and honor its trust responsibilities or special commitments to American Indians, Alaska Natives, and affiliated island communities. The mission of the Bureau of Reclamation is to manage, develop, and protect water and related resources in an environmentally and economically sound manner in the interest of the American public. Hyrum Dam Spillway Replacement Project Final Environmental Assessment Cache County, Utah Provo Area Office Upper Colorado Region prepared by Rick Baxter Manager, Water. Environmental, and Lands Division U.S. Department of the Interior Bureau of Reclamation Provo Area Office Provo, Utah August 2016 Contents Page Chapter 1 Purpose of and Need for Proposed Action ...................................... 1 1.1 Introduction ................................................................................................ 1 1.2 Background ................................................................................................ 2 1.3 Purpose and Need for the Proposed Action ............................................... 3 1.3.1 Need to Reduce the Risk of Potential Failure Modes ........................ 3 1.3.2 Increase Public Safety and Reduce the Risk of Loss of Human Life 4 1.3.3 Reduce Maintenance and Associated Costs ....................................... 4 1.4 Scoping ...................................................................................................... 4 1.5 Permits, Licenses, and Authorizations Required ....................................... 4 1.6 Related Projects and Documents ............................................................... 5 1.7 Scope of Analysis ...................................................................................... 5 1.8 Document Organization ............................................................................. 6 Chapter 2 Alternatives ........................................................................................ 7 2.1 Introduction ................................................................................................ 7 2.2 No Action Alternative ................................................................................ 7 2.3 Proposed Action Alternatives .................................................................... 7 2.3.1 Alternative 3....................................................................................... 9 2.3.2 Alternative 1a ..................................................................................... 9 2.3.3 Alternative 1b................................................................................... 10 2.3.4 Alternative 2a ................................................................................... 10 2.3.5 Alternative 2b................................................................................... 11 2.4 Project Design .......................................................................................... 12 2.5 Comparison of Alternatives ..................................................................... 12 2.6 Alternatives Considered and Eliminated From the Study ....................... 13 Chapter 3 Affected Environment and Environmental Consequences .......... 14 3.1 Introduction .............................................................................................. 14 3.2 Resources Eliminated from Analysis ....................................................... 14 3.3 Public Health and Human Safety ............................................................. 15 3.3.1 No Action Alternative ...................................................................... 15 3.3.2 Alternative 3..................................................................................... 15 3.3.3 Alternative 1..................................................................................... 15 3.3.4 Alternative 2..................................................................................... 16 3.4 Air Quality and Noise .............................................................................. 16 3.4.1 No Action Alternative ...................................................................... 16 3.4.2 Alternative 3..................................................................................... 16 3.4.3 Alternative 1.................................................................................... 16 3.4.4 Alternative 2..................................................................................... 17 3.5 Transportation and Roads ........................................................................ 17 3.5.1 No Action Alternative ...................................................................... 17 3.5.2 Alternative 3..................................................................................... 17 3.5.3 Alternative 1..................................................................................... 17 3.5.4 Alternative 2..................................................................................... 17 3.6 Soils and Farmlands ................................................................................. 18 3.6.1 No Action Alternative ...................................................................... 18 3.6.2 Alternative 3..................................................................................... 18 3.6.3 Alternative 1..................................................................................... 18 3.6.4 Alternative 2..................................................................................... 19 3.7 Socioeconomics ....................................................................................... 19 3.7.1 No Action Alternative ...................................................................... 19 3.7.2 Alternative 3..................................................................................... 19 3.7.3 Alternative 1..................................................................................... 19 3.7.4 Alternative 2..................................................................................... 19 3.8 Recreation ................................................................................................ 20 3.8.1 No Action Alternative ...................................................................... 20 3.8.2 Alternative 3..................................................................................... 20 3.8.3 Alternative 1..................................................................................... 20 3.8.4 Alternative 2..................................................................................... 20 3.9 Visual Resources ...................................................................................... 21 3.9.1 No Action Alternative ...................................................................... 21 3.9.2 Alternative 3..................................................................................... 21 3.9.3 Alternative 1..................................................................................... 21 3.9.4 Alternative 2..................................................................................... 21 3.10 Water Resources and Hydrology ........................................................... 22 3.10.1 No Action Alternative .................................................................... 23 3.10.2 Alternative 3................................................................................... 23 3.10.3 Alternative 1................................................................................... 23 3.10.4 Alternative 2................................................................................... 23 3.11 Operations .............................................................................................. 24 3.11.1 No Action Alternative .................................................................... 27 3.11.2 Alternative 3................................................................................... 27 3.11.3 Alternative 1................................................................................... 27 3.11.4 Alternative 2................................................................................... 27 3.12 Wetlands ................................................................................................ 27 3.12.1 No Action Alternative .................................................................... 28 3.12.2 Alternative 3................................................................................... 28 3.12.3 Alternative 1................................................................................... 28 3.12.4 Alternative 2................................................................................... 28 3.13 Vegetation and Noxious Weeds ............................................................. 28 3.13.1 No Action Alternative .................................................................... 29 3.13.2 Alternative 3................................................................................... 29 3.13.3 Alternative 1................................................................................... 29 3.13.4