PORT TOWNSEND — A preferred alternative to replace the south breakwater at Point Hudson could be under construction as early as winter 2021, an engineering firm said.
The proposal, presented Wednesday during a Port of Port Townsend commission workshop, would cost between $5.5 million and $6.5 million, and it would depend on timely permitting through the U.S. Army Corps of Engineers, according to a civil engineering firm based in Seattle.
Port commissioners still have to approve the project. They could discuss it as early as their next business meeting on Feb. 26.
Shane Phillips, the vice president and deputy coastal and ports practice leader for Mott MacDonald, told port commissioners the preferred alternative would replace the entire length of the existing south breakwater and replace it with new piles, rock and lagging in addition to a new timber walkway in the middle.
The south jetty replacement project has been ranked the top priority of the port’s capital projects since 2015.
Phillips presented three alternatives that ranged from encapsulating the existing structure to partial replacement with encapsulation in addition to full replacement.
The south and north breakwaters would be designed and permitted at the same time and likely would be constructed in phases, Phillips said.
He cautioned port commissioners about the permitting phase, saying the Corps has a large backlog of projects that could take between 18 and 36 months.
“It could be the winter of 2022 would be realistic for the first time you could get out there and work on the breakwater,” he said.
In addition to the corps, permitting would need to go through the National Marine Fisheries Service, Deputy Director Eric Toews said.
“I think putting our best foot forward early in the process is critical,” Toews said. “We want to have the best possible chance of having a self-mitigating project as possible.”
The breakwater replacement would be slightly smaller than the current footprint and would include the removal of creosote and other environmental impacts, Phillips said.
The proposal includes uncoated steel pipe piles, battered to match existing aesthetics, and the core would contain large, high-quality granite that likely would come from the Cascade mountains, Phillips said.
The piles would be taller than the existing structure to account for sea level rise, he added.
“Even at the height of the current structure, it’s still higher than Water Street,” Commissioner Bill Putney said.
The new structure would be built for a 30-year lifespan, Phillips added.
“The main thing is, you don’t want waves coming in and rolling right over the top of it,” he said. “If you have some over-topping, that’s acceptable because it wouldn’t affect the basin very much.”
The original structures were built by the military in 1934 and mostly used to offload supplies, Phillips said.
A major reconstruction took place in 1969 as it was converted to a small-craft harbor.
“The primary purpose is to protect the infrastructure in the marina,” Phillips said.
Two shoals exist inside the breakwaters to provide structure and ensure sediment doesn’t get into the waterway.
The last time the breakwaters were rehabilitated was in 1996, Phillips said.
Putney said one advantage with full replacement as the preferred alternative is more predictability with project bids because contractors won’t have to anticipate damaging parts of the structure that were meant to remain.
Community feedback on previous versions of a replacement plan raised concern about noise and vibrations from pile drivers and hammers, interim Executive Director Jim Pivarnik said.
“As we move forward, there was concern that all of downtown [Port Townsend] would be shaking for a period of months,” he said. “We just want to be sure we address that with the community and the contractor.”
Phillips said the soil conditions “aren’t horrible” from the perspective of using a vibratory hammer.
“This isn’t a huge pile hammer that’s going to be needed,” Phillips said. “There is some noise, but not as big or as noisy as they can be.”
Toews said there are a limited number of hammer blows allowed in a permit.
“Vibratory installation of piles really speeds up the process overall because you can get far more piles in with only proofing blows counted toward that hammer-blow count,” he said.
Jefferson County Managing Editor Brian McLean can be reached at 360-385-2335, ext. 6, or at [email protected].