Draft Environmental Assessment Phase 1 Rehabilitation San Carlos Irrigation Project Facilities Pinal County, Arizona U.S. Department of the Interior Bureau of Reclamation Phoenix Area Office June 2010 Draft Environmental Assessment Phase I Rehabilitation San Carlos Irrigation Project Pinal County, Arizona Prepared by EcoPlan Associates, Inc. 701 W. Southern Ave. Mesa, AZ 85210 (480-733-6666) and Bureau of Reclamation Phoenix Area Office 6150 W. Thunderbird Ave. Glendale, AZ 85306 (623-773-6256) June 2010 DISCLAIMER STATEMENT EcoPlan Associates, Inc., has been contracted by the Bureau of Reclamation to assist with the preparation of this Environmental Assessment. EcoPlan declares no financial or other interest in the outcome of the proposed project pursuant to the requirements of 40 CFR Section 1506.5. _____________________________________ __________________________________June16, 2010 F. Bruce Brown, Principal Date EcoPlan Associates, Inc. Mission Statements The mission of the Department of the Interior is to protect and provide access to our Nation’s natural and cultural heritage and honor our trust responsibilities to Indian Tribes and our commitments to 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. TABLE OF CONTENTS ACRONYMS AND ABBREVIATIONS...................................................................................... iv 1.0 PURPOSE AND NEED..........................................................................................................1 1.1 Introduction ..................................................................................................................1 1.2 Background ..................................................................................................................1 1.3 Purpose and Need for Action .......................................................................................3 1.3.1 Ashurst-Hayden Diversion Dam and Headworks...........................................3 1.3.2 Sediment Management....................................................................................4 1.3.3 Bank Protection...............................................................................................4 1.4 Project Location...........................................................................................................4 1.5 Decisions to Be Made...................................................................................................5 1.6 Public Involvement.......................................................................................................5 1.6.1 Scoping............................................................................................................5 2.0 DESCRIPTION OF ALTERNATIVES .................................................................................7 2.1 No Action.....................................................................................................................7 2.2 Proposed Action...........................................................................................................7 2.2.1 Rehabilitation of Ashurst-Hayden Diversion Dam and Headworks...............7 2.2.2 Armoring of the South Bank of the Gila River.............................................11 2.2.3 Construction and Operation of Sediment Removal and Storage Facility .....11 2.2.4 Additional Project-Related Actions ..............................................................14 2.2.5 Project Construction......................................................................................15 2.3 Alternatives Considered But Eliminated....................................................................16 2.3.1 Radial Gate Alternative.................................................................................16 2.3.2 Pilot Channel Alternative..............................................................................16 2.3.3 Slide Gate Alternatives.................................................................................16 2.3.4 Trash Management Alternatives ...................................................................17 2.3.5 Long-Term Sediment Storage Alternatives ..................................................17 3.0 AFFECTED ENVIRONMENT AND ENVIRONMENTAL CONSEQUENCES ..............18 3.1 Introduction ................................................................................................................18 3.2 Land Ownership, Jurisdiction, and Land Use ............................................................18 3.2.1 Affected Environment...................................................................................18 3.2.2 Environmental Consequences.......................................................................22 3.3 Visual Resources........................................................................................................24 3.3.1 Affected Environment...................................................................................24 3.3.2 Environmental Consequences.......................................................................24 Draft Environmental Assessment i Phase 1 Rehabilitation San Carlos Irrigation Project Facilities 3.4 Environmental Justice................................................................................................26 3.4.1 Affected Environment...................................................................................26 3.4.2 Environmental Consequences.......................................................................26 3.5 Cultural Resources.....................................................................................................27 3.5.1 Affected Environment...................................................................................27 3.5.2 Environmental Consequences.......................................................................32 3.6 Indian Trust Assets.....................................................................................................33 3.6.1 Affected Environment...................................................................................33 3.6.2 Environmental Consequences.......................................................................33 3.7 Geology and Soils ......................................................................................................34 3.7.1 Affected Environment...................................................................................34 3.7.2 Environmental Consequences.......................................................................35 3.8 Water Resources and Water Quality ..........................................................................36 3.8.1 Affected Environment...................................................................................36 3.8.2 Environmental Consequences.......................................................................37 3.9 Floodplains and Flooding...........................................................................................38 3.9.1 Affected Environment...................................................................................38 3.9.2 Environmental Consequences.......................................................................40 3.10 Biological Resources..................................................................................................41 3.10.1 Affected Environment...................................................................................41 3.10.2 Environmental Consequences.......................................................................49 3.11 Riparian Zones and Wetlands.....................................................................................53 3.11.1 Affected Environment...................................................................................53 3.11.2 Environmental Consequences.......................................................................53 3.12 Noise...........................................................................................................................53 3.12.1 Affected Environment...................................................................................53 3.12.2 Environmental Consequences.......................................................................54 3.13 Air Quality..................................................................................................................54 3.13.1 Affected Environment...................................................................................54 3.13.2 Environmental Consequences.......................................................................55 3.14 Hazardous Materials...................................................................................................57 3.14.1 Affected Environment...................................................................................57 3.14.2 Environmental Consequences.......................................................................57 4.0 CONSULTATION AND COORDINATION ......................................................................59 4.1 List of Agencies and Persons Contacted ....................................................................59 4.1.1 Indian Communities......................................................................................59 4.1.2 Congressional Delegation.............................................................................59 Draft Environmental