Posted on June 28, 2023
Harbors statewide must be dredged periodically to preserve necessary water depths.
A total of 28 harbors across the state are closely monitored and maintained by the U.S. Army Corps of Engineers. Over time, sediment and sand collect in the harbor areas, making it difficult for boats and barges to enter.
The Kaunakakai Harbor will undergo a month-long dredging process starting in October. The island depends on twice-weekly barge deliveries for food, gas and other essentials, which would not be able to dock if dredging is not done.
The last time Molokaʻi’s harbor was dredged was 50 years ago.
Nani Shimabuku, the operations and maintenance program manager for the Corps of Engineers Honolulu District, said that roughly 30,000 cubic yards of sediment, sand and mud have accumulated since that last maintenance dredging in 1973.
“It’s creating safety concerns for the vessels that utilize the harbor and so maintenance dredging is needed to remove that collection of accumulated sediment and to restore the harbor to the authorized original depth of minus 23 feet so that vessels can safely enter and exit and maneuver within the harbor area,” Shimabuku said.
She said normal harbor operations can continue uninterrupted while the work takes place. Over the course of a month, contractors will use equipment like a clamshell bucket crane barge and a dump scow, which holds and transports the material that’s collected.
The Kaunakakai Harbor is both a recreational and commercial harbor, shared by the DOBOR and the DOT harbors’ divisions.
“The sediment is going to be removed from the water by a clamshell bucket and it’s going to be placed into the dump scow and then once that dump scow is filled, a tug is going to push the scow out to an EPA ocean dredge material disposal site that’s located 30 miles north of Kahului, and that’s where it will get disposed of,” Shimabuku said.
The offshore disposal site requires approval and close monitoring by the Environmental Protection Agency.
Shimabuku said each county in Hawaiʻi has its own sediment disposal site located at least 10 miles from shore.
The Corps of Engineers held meetings over the past year with the Molokaʻi community to plan for the upcoming work. Similar maintenance is also planned at Maui’s Kahului Harbor, tentatively scheduled for late summer.
