Engineers have further investigated what type of breakwater the Haines Harbor expansion project should include, but borough officials say a decision on how to proceed won’t be made any time soon.
PND Engineers presented on the costs and benefits of three breakwater options – rubble-mound, wave barrier, and floating breakwater – Wednesday at the library.
In a draft report provided to the borough about a week ago, PND recommended the borough pursue a $16 million rubble-mound breakwater if time and money allow.
“Rubble-mound breakwaters are a reliable means of protecting a harbor and should have minimal maintenance required if quality rock is used. However, due to the need for foundation improvement at site and large volume of material needed for construction, a rubble-mound breakwater is the highest cost. A rubble-mound breakwater may also have a longer permitting timeline, and require larger mitigation costs, because of the larger footprint,” engineers said.
A metal wave barrier, which is what Skagway’s harbor uses, would cost $7.8 million initially, but would cost an additional $1 million to maintain over 50 years. A floating barrier would cost $11.5 million and allow for extra moorage space for vessels, but would provide the least amount of protection.
Harbormaster Phil Benner said the borough has less than $20 million to spend on the harbor project, and funneling $16 million into the breakwater alone would be ill-advised. “It would take every bit of money we had. All we would have is a breakwater and no harbor,” he said.
Benner said he personally would prefer the wave barrier. “It’s just like they have in Skagway and it seems to be working well there.”
A geotechnical survey, also performed by PND last fall, initially indicated a rubble-mound breakwater would be a “challenging engineering endeavor” because of the soft clay deposits and slope of the sea floor.
In the initial draft report, given to the borough in February, PND also recommended against the installation of wick drains, a means of building a rubble breakwater in soft soils, “based on the variable soil types encountered and the likelihood they would be difficult to install without being damaged and therefore would not perform as anticipated.”
However, in the new report and upon further investigation, PND concluded construction of the rubble-mound breakwater complete with wick drains is feasible.
Manager Mark Earnest said he doesn’t know when a decision on which path to pursue will be made. “I do not expect a quick decision on this because of the large range of costs versus benefits for the main design options,” Earnest said.
The decision ultimately rests with the assembly, but Benner said he hopes it will forward the report to the Port and Harbor Advisory Committee for its recommendation.