First Dredging in 30 Years for Naha Port
Naha Military Port, Okinawa, Japan, is currently undergoing its first dredging operation since 1989.
According to the U.S. Army, this major hub in shipping for military and other government service cargo is currently unable to support medium draft vessels for unit moves.
“We have a great team here with Military Sealift Command and U.S. Army Corps of Engineers,” said Lt. Col. Kelvin Simmons, 835th commander. “They are the experts on dredging. As far as I am concerned they are part of the team.”
“The powers that be argued for four years on whether the harbor would be dredged to 34 or 38 feet,” said Thomas Walters, director of MSC Okinawa.
Walters said that he recommended that they dredge to 38 feet so that they could accommodate more ships.
“If the depth had been 38 feet, 67 vessels, roll-on, roll-off (RO/RO), prepositioned cargo fleet, and surge fleet for sealift could all come in,” he said. “However, they are dredging to 34 feet, which will accommodate 26 ships; this will work for most contingencies.”
Not only is the channel being dredged for depth, it is also being widened to accommodate longer vessels.
“The requirement for the width of the channel must be 50 percent of the length of the vessel,” said Walters. “A 720-foot vessel can come in at 110 meters if the channel is straight. However, the channel at Naha has two doglegs, so we need it wider there.”
“The U.S. Army Corps of Engineers did the environmental survey and awarded the contract,” said David Barrett, construction control representative for the Corps of Engineers. “The contract was awarded in May 2018, preconstruction surveys were started this February, and dredging began in April.”
Barrett added that the biggest challenge of the project for the USACE was at the start: getting the permits and finding the right people. Mud that is hauled out of the harbor is treated to form a type of concrete.
“They are using a system that adds a hardening agent and makes it into a type of concrete at almost the same time it is dug out,” said Barrett. “They haul out 1,200 cubic meters a day, and they are turning that 1,200 around in a day. They have 45 dump trucks that are taking the finished product down to a landfill after it is processed.”