Exploring Deepwater World War II Battlefields in the Pacific Using Emerging Technologies

This research team sought to enhance our knowledge about this historic battlefield and the preservation status of the tangible reminders of an important moment in U.S. history.

To find previously unknown sites (e.g., shipwrecks, tanks, amphibious vehicles, aircraft) on this largely unexplored battlefield, the team tested a new approach. They used artificial intelligence to find potential sites in lidar data. With targets identified, they deployed technical divers to ground truth the data.

The divers investigated 14 lidar-detected targets outside of Saipan Lagoon at depths ranging from roughly 10 to 50 meters (33-164 feet). While lidar proved effective for detecting sites in shallower water, it was less effective at these greater depths, where most of the targets turned out to be natural features. Nevertheless, the team did discover a number of sites, including a large amount of iron anchor chain and an amphibious vehicle (a Landing Vehicle Tracked, or LVT).

Additional operations in this deep water included documenting, for the first time, a U.S. PBM Coronado seaplane and a multivehicle WWII LVT dump site, known only to a few local divers, and a tow board survey. During this survey, they documented a number of artifacts associated with WWII that were not evident in the lidar data, including iron plating, a possible LVT, ordnance, a potential mooring, and other battle-related items.

The team also visited 15 known sites in the shallower water of the lagoon (up to 12 meters [40 feet] in depth) that are on the Battle for Saipan Maritime Heritage Trail. Here, they conducted conservation surveys and photogrammetric surveys to create 3D models of the sites.

At six sites, inside and outside of the lagoon, they collected environmental DNA (eDNA) biofilm, water, and sediment samples to learn about the marine life associated with the sites.

Joining the project team were 8 U.S. military veteran divers from Saipan, who participated in this project as part of a citizen science rehabilitative therapy training program, as well as 12 veterans and family members from Task Force Dagger Special Operations Foundation. These individuals assisted with the investigation of potential targets, site documentation, and sample collection. Notably, veteran rebreather divers did most of the deepwater investigation of potential targets.

Other participants included Mariana Islands Nature Alliance rangers, recent high school graduates in training to become community conservation messengers. The rangers assisted with the processing of eDNA samples aboard the research vessel.

While the fieldwork is complete, more work remains to be done. It will take several months to build photogrammetric models from the diver- and ROV-collected imagery, process the eDNA data, and analyze the corrosion measurements collected during the conservation surveys. In addition, work will continue to refine the use of lidar for the detection of underwater cultural heritage sites.

All the data collected and processed during this project will provide a current snapshot of the condition of each site that can be used to track its health over time. They will also provide important insights into the factors that affect site integrity. eDNA data will shed light on site-specific species diversity, abundance, and sustainability. Together, these data will help marine resource managers understand the socioeconomic value of these important archaeological and biological resources (e.g., for historical, tourism, and fisheries purposes) to inform their protection and increase public appreciation and understanding of WWII maritime heritage.