Naha Military Port being deepened for the first time in 30 years

Naha Military Port. Credit: Lewis Tse Pui Lung/Shutterstock

For the first time in three decades, Naha Military Port is being dredged.

The facility in Okinawa, Japan, is home to the 835th Transportation Battalion, one of the 599th Transportation Brigade’s three forward battalions in the Pacific, and Military Sealift Command (MSC) Okinawa.

With a narrow mouth, Naha Military Port does not usually accommodate United States naval vessels, although MSC vessels regularly call at the facility. The port had a published draught of 10 m over the years, but the buildup of silt and other sediments resulted in the draught dropping to 8.4 m in some sections.

This has resulted in ships of more than 213 m not being able to enter the port.

Although there were requests to dredge Naha Military Port over the past three decades, the process was often delayed, and was complicated by unsuccessful attempts of the former Democratic Party of Japan-led government (2009–12) to relocate the US military base to another site in Okinawa.

In late 2016, the US Army Corps of Engineers (USACE) did the environmental survey and called for tenders in March 2017. In May 2018, the USD25.6 million dredging contract was awarded to a joint venture between two Japanese civil engineering and construction businesses, the Tokyo-based Maeda Corporation and the Okinawa-based Onaka Gumi Company.

Dredging commenced in mid-2019 and is expected to take two years to complete. The works will not only restore the published draught of 10 m, but also widened the port to take longer vessels.

There was some excitement in June 2019 when an unexploded bomb was found and towed away the following day.

The port has a width of 109.7 m at its narrowest point. The widest point of the inner harbour is 271 m. Thomas Walters, MSC Okinawa’s director, said that the requirement for the width of the channel must be 50% of the length of the vessel.

For the USACE, the biggest challenge was obtaining the permits, and the Japanese Coast Guard, Pilots’ Association, ferry captains, tourism industry, Department of Education archaeological office, Naha Port Authority, and the Okinawa Defense Bureau all had to come together and agree on the dredging. Mud that is dredged from the waters will be treated to form a type of concrete, and according to USACE’s construction control representative David Barrett, about 1,200 m³ of mud is dug out every day.