Environmental Assessment Imperial Dam Facilities Electrical Improvements U.S. Department of the Interior Bureau of Reclamation Yuma Area Office Yuma, Arizona July 2013 Mission Statements The U.S. Department of the Interior protects America’s natural resources and heritage, honors our cultural and tribal communities, and supplies the energy to power our future. 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. Environmental Assessment Imperial Dam Facilities Electrical Improvements Prepared by United States Department of the Interior Bureau of Reclamation Yuma Area Office 7301 Calle Agua Salada Yuma, Arizona 85364 i Acronyms and Abbreviations AAC All-American Canal AF Acre-Feet AGFD Arizona Game and Fish Department BMPs Best Management Practices BLM Bureau of Land Management Camp Imperial Dam Camp Site CFR Code of Federal Regulations EA Environmental Assessment EO Executive Order EPA Environmental Protection Agency ESA Endangered Species Act FONSI Finding of No Significant Impact HVAC Heating Ventilation and Air Conditioning ICAPCD Imperial County Air Pollution Control District IID Imperial Irrigation District ITAs Indian Trust Assets LCR Lower Colorado River LSB Laguna Settling Basin MSCP Multi-Species Conservation Program NAAQS National Ambient Air Quality Standards NWR National Wildlife Refuge NEPA National Environmental Policy Act NHPA National Historic Preservation Act NOx Nitrogen Oxides O3 Ozone O&M Operation and Maintenance PCBs Polychlorinated biphenyls PM10 Particulate Matter that is 10 microns in diameter or less Reclamation Bureau of Reclamation SHPO State Historic Preservation Office SCADA Supervisory Control and Data Acquisition US United States USFWS United States Fish and Wildlife Service USACE United States Army Corps of Engineers VOCs Volatile Organic Compounds YCEPD Yuma County Environmental Programs Division YCR Yuma clapper rail ii Contents Page 1.0 Purpose of and Need for Proposed Action ................................................... 1 1.1 Introduction ........................................................................................... 1 1.2 Location ................................................................................................ 1 1.3 Background ........................................................................................... 3 1.4 Purpose and Need ................................................................................. 3 1.5 Determinations to be Made ................................................................... 4 2.0 Alternatives Considered ................................................................................ 5 2.1 No Action Alternative ........................................................................... 5 2.2 Proposed Action .................................................................................... 5 2.2.1 Construction Activities ................................................................... 5 2.2.2 Maintenance Activities ................................................................... 8 3.0 Affected Environment and Environmental Consequences ................. 11 3.1 Land Use ............................................................................................. 11 3.1.1 Affected Environment ................................................................... 11 3.1.2 Environmental Consequences ....................................................... 11 3.1.3 Management and Mitigation Measures ......................................... 11 3.2 Air Quality .......................................................................................... 12 3.2.1 Affected Environment ................................................................... 12 3.2.2 Environmental Consequences ....................................................... 12 3.2.3 Management and Mitigation Measures ......................................... 12 3.3 Biological Resources .......................................................................... 13 3.3.1 Affected Environment ............................................................... 13 3.3.2 Environmental Consequences ................................................... 15 3.3.3 Management and Mitigation Measures ......................................... 15 3.4 Cultural Resources .............................................................................. 15 3.4.1 Affected Environment ................................................................... 15 3.4.2 Environmental Consequences ....................................................... 16 3.4.3 Management and Mitigation Measures ......................................... 16 3.5 Indian Trust Assets ............................................................................. 16 3.5.1 Affected Environment ................................................................... 16 3.5.2 Environmental Consequences ....................................................... 17 3.5.3 Management and Mitigation Measures ......................................... 18 3.6 Environmental Justice and Socio-Economic Conditions .................... 18 3.6.1 Affected Environment ................................................................... 18 3.6.2 Environmental Consequences ....................................................... 18 3.6.3 Management and Mitigation Measures ......................................... 19 3.7 Hazardous Materials or Solid Waste ................................................... 19 3.7.1 Affected Environment ................................................................... 19 3.7.2 Environmental Consequences ....................................................... 19 3.7.3 Management and Mitigation Measures ......................................... 20 3.8 Noise ................................................................................................... 20 3.8.1 Affected Environment ................................................................... 20 3.8.2 Environmental Consequences ....................................................... 20 3.8.3 Management and Mitigation Measures ......................................... 21 iii 3.9 Water Resources ................................................................................. 21 3.9.1 Affected Environment ................................................................... 21 3.9.2 Environmental Consequences ....................................................... 21 3.9.3 Management and Mitigation Measures ......................................... 22 3.10 Cumulative Effects of the Proposed Action........................................ 22 3.10.1 Impacts by Resource ................................................................. 23 4.0 Consultation, Coordination, and List of Preparers ............................. 26 4.1 Agencies Consulted ............................................................................ 26 4.2 List of Preparers .................................................................................. 26 4.2.1 Bureau of Reclamation ................................................................. 26 5.0 References ................................................................................................ 27 Appendices Appendix A. Draft Environmental Assessment Notice of Availability Appendix B. Section 106 Consultations iv 1.0 Purpose of and Need for Proposed Action 1.1 Introduction The Bureau of Reclamation (Reclamation) has prepared this environmental assessment (EA) to evaluate potential impacts associated with the proposed electrical improvements to the Imperial Dam facilities. This EA was prepared in accordance with the National Environmental Policy Act (NEPA) of 1969 (42 UCS 4321 et seq.), the Council on Environmental Quality regulations (40 CFR 1500-1508) for implementing NEPA, and the Department of the Interior’s NEPA Regulations (43 CFR Part 46), and Reclamation Manual NEPA Policy (ENV P03). Reclamation is the lead Federal agency pursuant to NEPA. 1.2 Location Imperial Dam is located along the lower Colorado River (LCR), approximately 18 miles northeast of Yuma, Arizona. The project is located in the Imperial and Laguna Divisions of the LCR. The project area lies on both the Arizona and California side of the river in Yuma and Imperial Counties, at approximate River Mile 49.3, see Figure 1 for project location. 1 Figure 1. Location Map 2 1.3 Background Imperial Dam was constructed between 1936 and 1938 under the authorization of the Boulder Canyon Project Act of 1928 to divert water from the Colorado River to the All-American Canal (AAC) and the Gila Gravity Main Canal. The project delivers irrigation water, through irrigation districts, to over 600,000 acres of farmland in Arizona and California, and to municipalities that are dependent on Colorado River water for consumptive use. The Imperial Dam facilities are owned by Reclamation. The Imperial Irrigation District (IID), in accordance with contractual agreements with Reclamation’s Yuma Area Office, has operation and maintenance responsibility for the facilities, including: Imperial Dam, Gila Canal headworks, and the AAC. Imperial Dam is approximately 3,479 feet long. The Imperial Dam facilities consist of seven sections that include the California abutment, the AAC headworks, the sluiceway, the overflow weir section, the Gila Canal headworks, the Arizona abutment, and the Arizona dike. The AAC trashrack and headgates are located