State project to improve Hāna bridges gets finding of no significant environmental impact

A $40 million project to improve the safety and public use of a half-dozen Hāna Highway bridges while retaining their historic character has received a finding of no significant environmental impact, according to the Hawaiʻi Department of Transportation.

The finding and a final project environmental assessment are included in the Sept. 23 issue of The Environmental Notice issued by the state Office of Planning and Sustainable Development.

Construction of the bridge repairs is anticipated to begin in 2025 after final project designs are completed and all necessary permits and approvals are secured. Construction work is expected to be ongoing for two to three years.

“The project’s purpose is to address existing structural deterioration and sub-standard structural conditions by improving the bridges to be consistent with current standards and guidelines for load capacity, bridge railing and transitions, and seismic and scour standards,” the final environmental assessment says. “The project would improve the six bridges in a context-sensitive manner so they remain functional for highway users and local and regional communities.”

“Context-sensitive” means project designs will consider “the surrounding environment and communities they serve.” The project is a partnership between the Hawaiʻi Department of Transportation and the Federal Highway Administration, Central Federal Lands Highway Division.

The six bridges affected by the improvement project are those spanning the Kailua, Makanali, Puohokamoa, Kopiliula, ʻUlaʻino and Mokulehua streams. The streams are all on the northeast coast of Maui between Haʻikū-Paʻuwela and Hāna.

In five of the projects (all except Kopiliula), the work will entail building a “context-sensitive superstructure replacement” while retaining the existing bridge substructure/foundation. For the Kopiliula Stream bridge, the existing structure will be retained while a “context-sensitive structure” will be built makai of the existing one.

The design goal is to retain the historic appearance of the bridges, including character-defining abutments and piers, while providing a new, single-span structure within that covers the existing support structure.

“By doing this, the existing substructures would remain in place and provide a similar visual appearance to the existing structure,” the final environmental assessment says. “The concrete superstructures would be designed to match the existing historic features best while also meeting project design criteria.”