The Coupeville ferry dock will be closed this weekend as workers drive piles into the soggy floor of the Sound.

A $1.9-million seismic retrofit project has been going on for weeks, but this stage of work requires the run between Coupeville and Port Townsend to be closed Saturday, Nov. 5 and Sunday, Nov. 6, according to officials with Washington State Ferries.

Sailings between Coupeville and Port Townsend are scheduled to resume at 6:30 a.m. Monday, Nov. 7, but reservations are blocked that day in case work extends past Sunday night and results in unplanned delays.

The closure means people hoping to travel between the Coupeville and Port Townsend must find an alternate — and probably less-convenient — route.

The Silverdale’s Klahowya Secondary School volleyball team, for example, qualified for the District 3 1A Tournament hosted by Coupeville Saturday.

To get to Coupeville, the Klahowya team and fans will now have to make two ferry trips, first crossing at Kingston, and then catch the ferry from Mukilteo to Clinton, adding at least an hour to the journey.

The project will create better support for the dock’s timber towers, also known as transfer span towers.

Once completed, the dock should be able to continue operating in the event of a 100-year seismic event.

The work will make the structure safer for a 1,000-year event, according to a Ferries spokesman.

Because the work is in the water, the project was published in the Federal Register. Noise from the pile driving is identified as causing “level B” harassment of marine mammals.

The ferry runs is popular with tourists. The ridership for the Coupeville ferry last year increased 8.9 percent to a total rider number of 787,391, according to State Ferries.