Using Photogrammetry and Deviation Analysis to Conduct Quantitative Monitoring Surveys of WWII Sites in the Pacific.

In 2012 a program to investigate the management of underwater cultural heritage (UCH) related to the WWII battle for Saipan was developed with several collaborative partners. The program was conceptualized in response to the creation of the WWII Battle for Saipan Underwater Heritage Trail that launched in 2010 (McKinnon and Carrell in J Maritime Archaeol 10(1):11–27, 2015). With the creation of the trail there became a need to monitor and record both the benefits and impacts of promoting visitation at UCH sites. The monitoring program began on a five-year interval and included archaeological site inspections and the collection of in situ conservation data in 2012 and 2017. In 2017, as photogrammetric survey data was advancing and becoming more useful, it was added to the monitoring program. Again in 2023, site inspections, in situ surveys, and photogrammetric surveys were undertaken providing a total of 15 years of data at five-year intervals. This data has proved invaluable for recording both qualitatively and quantitatively how these WWII submerged sites are changing over time. This article reports on the development of photogrammetric surveys and the use of deviation analysis to demonstrate natural and cultural changes on UCH sites of a WWII battlefield from 2017 to 2023. [ABSTRACT FROM AUTHOR]