B.F. Sisk Dam Raise and Reservoir Expansion Project Environmental Impact Report/ Supplemental Environmental Impact Statement DRAFT Estimated Lead Agency Total Costs Associated with Developing and Producing this EIR/SEIS is $1,348,000 August 2020 B.F. Sisk Dam Raise and Reservoir Expansion Project Draft Environmental Impact Report/Supplemental Environmental Impact Statement Draft Estimated Lead Agency Total Costs Associated with Developing and Producing this EIR/SEIS is $1,348,000 August 2020 Mission Statements The mission of the Department of the Interior is to conserve and manage the Nation’s natural resources and cultural heritage for the benefit and enjoyment of the American people, provide scientific and other information about natural resources and natural hazards to address societal challenges and create opportunities for the American people, and honor the Nation’s trust responsibilities or special commitments to American Indians, Alaska Natives, and affiliated island communities to help them prosper. 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. The mission of the San Luis & Delta-Mendota Water Authority is to operate the Delta-Mendota Canal and related facilities reliably and cost- effectively, and to support member agencies in restoring and protecting adequate, affordable water supplies for agricultural, municipal and industrial, and environmental uses. B.F. Sisk Dam Raise and Reservoir Expansion Project Draft Environmental Impact Report/Supplemental Environmental Impact Statement Lead Agencies: San Luis & Delta-Mendota Water Authority (SLDMWA) and the United States Department of the Interior, Bureau of Reclamation (Reclamation) Cooperating Agencies and Responsible Agencies: California Department of Transportation (Caltrans) The project is located in the following counties in California: Contra Costa, Fresno, Imperial, Kern, Kings, Los Angeles, Merced, Orange, Riverside, San Benito, San Bernardino, San Diego, San Joaquin, San Luis Obispo, Santa Clara, Stanislaus and Ventura Counties State Clearing House Number: 2009091004 ABSTRACT The Draft EIR/SEIS evaluates increasing storage capacity in San Luis Reservoir to provide greater water supply reliability for South-of-Delta Central Valley Project (CVP) and State Water Project (SWP) water contractors. Increased capacity within San Luis Reservoir would only be used to help meet existing demands and would not serve any new demands in the South-of-Delta CVP and SWP service areas. In addition to the No Project/No Action Alternative, this EIR/SEIS evaluates a 1) a Non-Structural Alternative under which operational modifications in San Luis Reservoir would be used to provide operation flexibility; and (2) a Dam Raise Alternative under which B.F Sisk Dam would be raised an additional 10 feet above the 12-foot embankment raise under development by the B.F. Sisk Dam SOD Modification Project. FOR FURTHER INFORMATION, CONTACT: Casandra Arthur Pablo Arroyave Bureau of Reclamation San Luis and Delta-Mendota Water Willows Construction Office Authority 1140 W. Wood Street 842 6th Street Willows, CA, 95988. Los Banos, CA 93635 Phone: (530) 892-6202 Phone: 209-833-1034 Email: [email protected] Email: [email protected] Contents Page Executive Summary ............................................................................................................. ES-1 ES.1 Purpose of this Environmental Impact Report/Supplemental Environmental Impact Statement ................................................................................................................................. ES-1 ES.2 Project Background and History .............................................................................................. ES-1 ES.3 Project Purpose and Need/Project Objectives ...................................................................... ES-2 ES.4 Study Area .................................................................................................................................... ES-3 ES.5 Alternatives Evaluated in this EIR/SEIS ............................................................................... ES-3 ES.6 Impact Summary ......................................................................................................................... ES-5 ES.7 Environmentally Superior Alternative ..................................................................................... ES-9 Chapter 1 Introduction ................................................................................................ 1-1 1.1 Project Background and History .................................................................................................... 1-1 1.2 Project Purpose and Need/Project Objectives ............................................................................ 1-3 1.3 Public Involvement .......................................................................................................................... 1-4 Chapter 2 Proposed Action and Description of Alternatives ...................................... 2-1 2.1 Alternative Formulation .................................................................................................................. 2-1 2.2 Proposed Alternatives ...................................................................................................................... 2-2 2.3 Mitigation Measures Implemented Under the B.F. Sisk Dam SOD Modification Project ....................................................................................................................................... 2-11 2.4 Environmentally Superior Alternative ......................................................................................... 2-14 Chapter 3 Affected Environment / Environmental Setting ........................................ 3-1 3.1 San Luis Reservoir ............................................................................................................................ 3-2 3.2 Sacramento-San Joaquin River Delta ............................................................................................. 3-7 3.3 Air Quality and Greenhouse Gases ............................................................................................... 3-9 3.4 Cultural Resources in Study Area ................................................................................................. 3-12 3.5 Paleontological Resources in Study Area .................................................................................... 3-16 3.6 Fisheries Resources in Study Area ............................................................................................... 3-16 3.7 Terrestrial Resources in Study Area ............................................................................................. 3-17 3.8 Regulatory Setting ........................................................................................................................... 3-20 Chapter 4 Environmental Consequences/ Environmental Impacts .......................... 4-1 4.1 Water Quality .................................................................................................................................... 4-2 4.2 Surface Water Supply ....................................................................................................................... 4-5 4.3 Air Quality ......................................................................................................................................... 4-9 4.4 Greenhouse Gases .......................................................................................................................... 4-12 4.5 Visual Resources ............................................................................................................................. 4-14 4.6 Noise ................................................................................................................................................. 4-16 4.7 Traffic and Transportation ............................................................................................................ 4-19 4.8 Hazards and Hazardous Materials ................................................................................................ 4-22 4.9 Aquatic Resources .......................................................................................................................... 4-25 4.10 Terrestrial Resources .................................................................................................................... 4-28 4.11 Recreation ...................................................................................................................................... 4-35 i DRAFT – August 2020 B.F. Sisk Dam Raise and Reservoir Expansion Project Draft Environmental Impact Report/Supplemental Environmental Impact Statement 4.12 Cultural Resources ........................................................................................................................ 4-38 4.13 Geology, Seismicity, and Soils .................................................................................................... 4-42 4.14 Public Utilities and Power ........................................................................................................... 4-45 4.15 Mitigation Measures Proposed under the Proposed Action .................................................. 4-47 Chapter 5 Cumulative Effects .....................................................................................