Rehabilitation of another Hamakua bridge is scheduled to begin early next year.
The Nanue Stream Bridge, located at about the 15 mile marker on Highway 19 — just south of Ninole — is slated for a three-year repair project that will replace large sections of infrastructure that have become dangerously degraded.
According to a draft environmental assessment for the project that was published Saturday, the state Department of Transportation has determined that the bridge — which was built in 1952 and, at 286 feet, is the tallest on the island — is in poor condition, listing problems including undermined bridge footings, missing or corroded rivets, “advanced deterioration” of trestles and girders, and more.
The project will not include any enhancements for the bridge, such as widening the road or adding bike lanes, said DOT spokeswoman Shelly Kunishige.
Kunishige on Wednesday said the cost of repairing the bridge has been estimated at roughly $80 million. Back in 2022, the project’s price tag was estimated at roughly $25 million.
In January, the U.S. Department of Transportation awarded the state $74.6 million in grant funding to repair both the Nanue bridge and the nearby Hakalau Stream Bridge.
Kunishige said the Nanue project is on schedule to begin in early 2025 and will take approximately 36 months to finish, with a completion date forecasted for early 2028.
The draft EA notes the project is inherently time-consuming, because replacing deteriorated girders while maintaining the bridge’s structural integrity requires that only a limited number of beams can be removed at any one time.
During the process, single-lane contraflows will be established to keep the bridge open to traffic, although the assessment states that total closures of the bridge might be necessary for brief periods. Kunishige said that it’s still too early to say when those closures might take place, because DOT hasn’t yet selected a contractor for the project.
The Nanue project is one of three Hamakua bridge repair projects that will be taking place concurrently with one another. Kunishige said rehabilitation of Hakalau bridge should begin in late 2025, and the next phase of the rehabilitation of Kolekole bridge should begin by the summer of 2027.
With the publication of the assessment — which anticipates that the project will have no significant environmental impact — a 30-day public comment period has begun and will end on July 7. Comments can be sent to HonoluluPlanning@wsp.com and the assessment can be read at tinyurl.com/yckxazzm.
Email Michael Brestovansky at mbrestovansky@hawaiitribune-herald.com.
