The replacement of damaged piles at the Navy’s Ammunition Wharf at Naval Magazine Indian Island won’t have water-quality impacts that violate state or federal laws, according to a recent environmental assessment by the Navy.

The draft study also said effects on air quality from the project would be negligible, and replacing the piles would not harm recreational and commercial fishing or shellfish harvesting.

The work would include replacement of up to 120 piles; including structural concrete piles, steel fender piles, and composite fender piles. A maximum of 22 piles could be installed each year depending on the results of biennial pile inspections, according to the study.

Construction and demolition at the Navy installation is expected to take place over a seven-year period, estimated to begin in 2023 and end in 2030.

Naval Magazine Indian Island provides munitions support to Navy, Joint and Allied vessels and is home to the U.S. Navy’s only deep-water ammunition port on the West Coast and the Department of Defense’s largest conventional ordnance storage site on the West Coast.

The Ammunition Wharf was built in 1979, and officials later learned that the precast concrete piles used for the pier were “susceptible to a potentially catastrophic condition called Delayed Ettringite Formation,” the new assessment notes. Delayed Ettringite Formation, a result of high early temperatures in the concrete, can happen rapidly and without warning, causing the concrete piles to expand and crack.

Navy officials said that of the 1,391 piles that support the Ammunition Wharf, there are 1,119 original piles that are susceptible to Delayed Ettringite Formation.

A total of 86 piles support the operations building on the pier, and 37 of them may be impacted by Delayed Ettringite Formation, according to the Navy report.

The Navy has conducted 10 earlier pile replacement projects at the base since 1998, with the last in 2020, which saw nine structural concrete piers replaced at the wharf.

The environmental assessment noted the last inspection of the waterfront facilities was done in 2021, and the inspection indicated 158 structural piles were “observed to have appreciable levels of [Delayed Ettringite Formation].” Ten had advanced damage and needed near-term replacement, along with three piles that support the operations building.

According to the environmental analysis, a maximum of 22 structural and fender piles would be replaced per year.

Noise impacts from construction are expected to  be temporary, occurring between Oct. 1 and Jan. 15, and the maximum expected duration of pile driving in a single day would be up to 1.5 hours of impact pile driving, according to the Navy study.

Temporary construction noise would be limited to 7 a.m. and 7 p.m. on weekdays.

The study also looked at how the pile replacement project would could impact marine sediments, biological resources, and American Indian traditional resources.

Tribal access to traditional resources will not be impacted by the pile replacement project, according to the study.

According to the report, the Navy invited the Suquamish Tribe, Port Gamble S’Klallam Tribe, Lower Elwha Klallam Tribe, and the Jamestown S’Klallam Tribe to initiate government-to-government talks on the project last year.

In November, the Port Gamble S’Klallam Tribe stated the project could proceed as planned with continued government-to-government consultation with the Tribe. 

The Port Gamble S’Klallam Tribe has asked the Navy that in the event of an inadvertent discovery of cultural resources, including ancestral remains, all work would halt and that the Tribe would be contacted immediately.

The environmental assessment was completed in June, and the Navy is accepting public input on the draft analysis through Friday, July 29.

The draft assessment can be found at navfac.navy.mil/NWNEPA for review and comment.

Written comments can be sent by email to NWNEPA@navy.mil.