At the time of the Final EIS publication, the Service Pier Extension (SPE) project had not yet been funded by Congress or programmed for implementation, prompting the Navy to defer a decision about the SPE in the Record of Decision (ROD). The signed ROD for the EIS was only for the Land-Water Interface (LWI) project. Subsequent to the 2016 ROD, the U.S. Congress approved funding for the SPE project and the Navy updated the design, planned construction methods, and timing for the pier extension and associated upland development.

In addition, in August 2016 the National Marine Fisheries Service (NMFS) finalized new technical guidance for assessing underwater noise effects on marine mammals, which influenced requirements for regulatory consultation under the Endangered Species Act (ESA) and the Marine Mammal Protection Act (MMPA).

Based on the project changes and the new regulatory guidance, the Navy determined that preparation of a Supplemental EIS (SEIS) was appropriate.

The purpose of the SPE is to provide additional maintenance berthing capacity and improve associated support facilities for existing homeported and visiting submarines at NAVBASE Kitsap Bangor.

The SPE project is needed to:

• Provide alternative opportunities for berthing to mitigate restrictions at NAVBASE Kitsap Bremerton on navigating SEAWOLF Class submarines through Rich Passage under certain tidal conditions.
• Improve long-term operational effectiveness for the three SEAWOLF Class submarines on NAVBASE Kitsap.
• Provide berthing and logistical support for SEAWOLF, LOS ANGELES, and VIRGINIA submarine classes at the Navy’s submarine research, development, test and evaluation hub, which is currently located on NAVBASE Kitsap Bangor.
• Improve submarine crew training and readiness through co-location of command functions at NAVBASE Kitsap Bangor submarine training center.

The Navy made some changes to the design, planned construction methods, and construction timing for the SPE project, but the project still involves essentially the same two action alternatives (a “short-pier” extension and a “long-pier” extension) that were evaluated in the 2016 Final EIS. As required by NEPA, a No Action Alternative has also been evaluated, but this alternative did not change between the 2016 EIS and the current SEIS and is therefore incorporated into the SEIS by reference. The SEIS addresses only the SPE project as a continuation of the NEPA process for the overall LWI-SPE action. The SEIS incorporates by reference all appropriate SPE-related information and analyses that did not change since the 2016 Final EIS.

Changes to Alternative 2 (short pier) would include the following:

• a reduction in the length of the pier extension from 540 feet to 520 feet
• a reduction in the total overwater area of the pier infrastructure (including floats, mooring dolphins, and wave screen) from 44,000 to 38,924 sq ft
• replacement of 27 permanent 36-inch diameter steel piles with 27 temporary “falsework” piles (also 36-inch diameter steel)
• installation of two fewer permanent 18-inch concrete fender piles (from 105 to 103 concrete piles)
• a decrease in the total area displaced by piles (from 1,965 to 1,808 sq ft)
• a decrease in the total area of benthic disturbance from permanent piles (from 12,753 sq ft to 11,358 sq ft). Note: the total area of benthic disturbance was calculated by adding to the area of pile displacement a two-foot radius around each permanent pile, to account for scour and shell hash deposition around the base of the new piles over time; while such a calculation did not appear in the 2016 Final EIS, it has been applied here using the same method for both the 2016 EIS and the SEIS project alternatives to facilitate comparison of the undersea project footprints
• an increase in the area displaced by temporary piles (from 0 to 192 sq ft)
• a one day decrease in the estimated total number of days of in-water pile driving (from an estimated 161 days to 160 days)
• a reduction in the maximum allowable number of impact pile driver strikes during any construction day from 2,000 strikes/day in the Final EIS to 1,600 strikes/day for Alternative 2 in this SEIS (impact pile driving would occur less than 45 minutes/day)
• increased use of vibratory pile driving and decreased use of impact pile driving due to the replacement of 27 permanent steel piles (both vibratory and impact driving) with 27 temporary falsework piles (vibratory only), and the installation of two fewer permanent concrete piles (impact driving); the quieter vibratory pile driving may occur on the same days as the louder impact pile driving, though not simultaneously, and for no more than 5 hours/day)
• an additional 4 acres (for a total of 7 acres) of upland area permanently disturbed due to a change in design of the upland development to include a permanent gravel-covered storage/laydown area instead of revegetation of the 4 acres as proposed under Alternative 2 of the Final EIS

Changes to Alternative 3 (long pier) would include the following:

• installation of 50 temporary falsework steel piles (36-inch diameter) that were not part of the 2016 Final EIS alternative, which would support the construction phase only (and be removed upon completion of construction)
• an additional 353 sq ft of area (temporarily) displaced by the 50 falsework piles
• an additional 4 acres (for a total of 7 acres) of upland area permanently disturbed due to a change in design of the upland development to include a permanent gravel-covered storage/laydown area instead of revegetation of the 4 acres as proposed under Alternative 3 of the Final EIS

Construction of the SPE project is now planned to be implemented in a two-phase process, with each phase estimated to last 2 years:

• Phase 1 includes waterfront construction of the pier extension (including support facilities on the pier) and the upland development of both a construction laydown/staging area and a new 420-space parking lot (with associated road and utility improvements)
• Phase 2 includes construction and operation of an upland waterfront ship support building at the site of an existing parking lot

Phase 1 construction of the pier extension, parking lot, and laydown area (with associated road and utility improvements) is estimated to begin in the Spring of 2019 and require approximately 26 months to complete. Proposed operations at the Phase I facilities are therefore estimated to begin in the Fall of 2021. Phase 2 construction of the upland ship support building is estimated to begin after completion of Phase 1 construction (Summer of 2021), and would require approximately 2 years to complete (Summer of 2023). Compared to the action evaluated in the 2016 Final EIS, this proposed timing represents an extension of the overall period during which construction activities would occur from an estimated 2 years to approximately 4 years.

Changes in design and construction methods and the new guidance for marine mammal noise effects required updated analysis of the following resources areas:

• Marine water resources
• Marine vegetation and invertebrates
• Fish
• Marine mammals
• Marine birds
• Geology, soils, and water resources
• Native American traditional resources and tribal treaty rights.
• Cumulative Impacts

The other resources evaluated in the 2016 EIS were considered relative to the project design and other changes and it was determined that the impact assessments from the EIS were still relevant. All such assessments were incorporated by reference in the SEIS.

The Navy is committed to protecting the environment and minimizing potential environmental effects, during the proposed construction and operation of the SPE project. As part of the Proposed Action, the Navy would implement appropriate Best Management Practices, Current Practices, mitigation measures, compensatory mitigation, and Treaty mitigation to minimize, mitigate, and offset impact on the community and the environment.

The Proposed Action would require pile driving, which may result in adverse effects on the community, wildlife and marine life. The Navy would implement several mitigation measures to reduce noise impacts, including:

• Performing in-water construction work from July 16 to January 15 to minimize impacts to juvenile Pacific salmon as this is the timeframe in which they are least likely to be present.
• Using vibratory methods for pile installation rather than impact methods whenever possible to reduce sound levels.
• Using air bubble curtains or other noise attenuating devices during impact pile driving to reduce underwater pile driving noise.
• Using a “soft-start” approach for impact pile driving to induce marine mammals to leave the immediate pile driving area.
• Restricting the duration of pile-driving activities in any given day (less than 45 minutes/day for the louder impact driving and no more than 5 hours/day for vibratory pile driving).
• Implementing marine mammal and marbled murrelet monitoring during construction to reduce impacts on these protected species.

Underwater noise from pile driving may impact adult salmon and steelhead that would be returning to Hood Canal during the in-water work window and would ordinarily be fish harvested by the tribes. The noise disturbance may cause these species to move to other areas of Hood Canal to avoid the noise. This would not result in a net loss of tribal resources, but could increase the time for the Tribes to harvest fish. The Navy, as part of ongoing government-to-government consultations, has developed treaty mitigation measures in consultation with affected tribes.

The Navy has developed a Mitigation Action Plan, specific to the SPE project, that includes best management practices, current practices, and mitigation measures to avoid, reduce and mitigate the potential effects of the proposed construction and operation of the SPE.

For each category of best management practice, current practices, and mitigation measures, the Mitigation Action Plan provides the following information:

• Description of the measure
• Parties responsible for implementation
• Planned implementation schedule
• Planned funding
• Mitigation-specific performance criteria
• Monitoring and tracking mechanisms
• Enforcement measures
• To offset unavoidable impact on aquatic resources, the Navy proposes to purchase habitat credits from the Hood Canal In-Lieu Fee Program, which would implement appropriate mitigation in the Hood Canal Watershed. The In-Lieu Fee Program is described in Section 6 of the Mitigation Action Plan.
• The Navy would undertake mitigation projects to address potential effects of the SPE on reserved Treaty rights and resources of affected American Indian Tribes. These projects would have been planned in consultation with the affected tribes. The Navy’s proposed Treaty mitigation projects are described in Section 9 of the Mitigation Action Plan.

The U.S. Army Corps of Engineers, Seattle District, and the National Marine Fisheries Service Headquarters are cooperating agencies for the SPE project. Agencies with permitting authority or jurisdictional responsibilities include:

• National Marine Fisheries Service
• U.S. Army Corps of Engineers
• U.S. Fish and Wildlife Service
• Washington Department of Ecology
• Washington Department of Archeology and Historic Preservation