(BIVN) – The planned rehabilitation of the Nanue Stream Bridge on the Hāmākua coast is detailed in a draft environmental assessment, published in the June 8 issue of The Environmental Notice. 

The Hawaiʻi Department of Transportation anticipates a finding of no significant impact.

The project costs are estimated at $75 million, the 746-page document states, with construction taking four years to complete.

From the document:

The proposed action rehabilitates the Nanue Stream Bridge to address deterioration of the structure by (1) replacing in-kind steel truss members, bearings, gusset plates, etc. that have corrosion and section loss; (2) addressing spalls and delamination in the concrete deck, abutments, bridge railings and column pedestals; (3) cleaning and painting the steel members following the repairs; and (4) addressing scour deficiencies for the bridge foundations.

Map from Nanue Stream Bridge Rehabilitation – Draft EA

Rehabilitation is the preferred alternative. Also considered were a “no build” alternative, a new bridge alternative, and a “rehabilitation with a new hybrid trestle”.

Officials hope to finish the final design of the project by mid-summer, with construction completed by spring 2028. According to the draft EA:

The work to be performed is to replace the bridge bearings and steel members (trestles, girders, etc.) with in kind materials. Work is anticipated to be done top down by staging on the bridge and lowering materials into position to replace members. The superstructure will be temporarily supported at each frame with temporary diagonal and horizontal bracing. The existing frame member will be removed and the new member will be installed. Each member will be replaced one by one until the trestle is completed. The contractor will move to the next trestle until all of the trestles are completed. Construction is intended to be completed while the bridge is open to public traffic. Contraflow traffic is required while construction is ongoing. Intermittent full bridge closures may be required at times during equipment and material placement. Discussions regarding lead remediation of the soil beneath the bridge structure is ongoing with the Department of Health. If soil lead remediation is required, an additional $10 million dollars would be required.

Comments on the draft EA are due by July 8, 2024.