The United States Department of the Navy (DON; Navy) has prepared this document to supplement the impact analyses contained in the Final Environmental Impact Statement (FEIS) for “Developing Home Port Facilities for Three Nimitz-Class Aircraft Carriers in Support of the U.S. Pacific Fleet” (the 1999 FEIS) in light of current circumstances and information. The 1999 FEIS addressed the environmental consequences of homeporting an additional 2 nuclear powered aircraft carriers (CVNs) (for a total of 3) at Naval Air Station North Island (NASNI) located at the north end of Coronado Island in San Diego County, California.

This Supplemental Environmental Impact Statement (SEIS) analyzes information that was not available at the time the 1999 FEIS was completed, and focuses on potentially significant new circumstances or information relevant to environmental conditions that have occurred since the 2000 Record of Decision (ROD) for the 1999 FEIS (dated 28 January 2000, published in the Federal Register (FR) on February 8, 2000 (65 FR 6181) and hereafter referred to as the “2000 ROD”). Information or circumstances that have not undergone significant change since the 2000 ROD are not re-examined. By supplementing the 1999 FEIS, this SEIS advances the purpose of the National Environmental Policy Act (NEPA) of informing Navy decision-makers and the general public about the environmental effects of the government’s action.

This SEIS is prepared in accordance with Council on Environmental Quality (CEQ) regulations (40 Code of Federal Regulations (CFR) Part 1500); NEPA (42 United States Code (USC) 4321); United States (U.S.) Navy procedures for implementing NEPA (32 CFR Part 775); Secretary of Navy Instruction (SECNAVINST) 5090.6A; and the guidelines contained in the Chief of Naval Operations Environmental and Natural Resources Program Manual Instruction (OPNAVINST) 5090.1C, 30 October 2007. The guidance for a supplemental environmental document is contained in 40 CFR 1502.9 and this SEIS has been prepared consistent with this guidance.

A primary focus of the SEIS is on vehicular traffic and traffic-related issues. The document evaluates the effectiveness of traffic mitigation measures implemented pursuant to the 2000 ROD, and reevaluates the 1999 FEIS traffic impact analysis in light of new circumstances or information relevant to traffic conditions. Among these changes is an anticipated increase in the average number of intermittent, nonconsecutive days each year (from 13 to 29) when the 3 CVNs homeported at NASNI are in port simultaneously. The SEIS also evaluates the infrastructure improvements included in military construction (MILCON) project (P-704) for Berth LIMA at NASNI, which were not required or implemented at the time the 1999 FEIS and 2000 ROD were prepared. Finally, the SEIS addresses public scoping comments related to off-site shoreline erosion. During the scoping process, public comments relating to shoreline erosion along First Street in the City of Coronado were raised. This SEIS responds to these comments by analyzing current erosion conditions in comparison to past and previously anticipated conditions.