The U.S. Department of Defense (DoD) has responsibility for human safety and environmental stewardship for coastal ranges and for abandoned ordnance unintentionally left underwater as a result of historic military activities. To address these concerns, the Navy through its Navy Environmental Sustainability Development to Implementation (NESDI) Program funded a program to assess the environmental effects of underwater unexploded ordnance (UXO). The site conceptual model (SCM) developed under this program identified the inability to predict the mobility and burial of UXO underwater as a critical gap in capability. To meet this need, the Naval Facilities Engineering Command Engineering Service Center (NAVFAC ESC) initiated a project to modify the existing vortex lattice model, which is used to predict mine mobility and burial. The new software is called the UXO Mobility Model (MM). Using the MM, it is possible to predict the fate of UXO over the broad range of coastal diversity where UXO is known to exist.

The objective of this project was to calibrate and validate the UXO MM for the two most common geomorphic coastal environments in which UXO are known to exist--the trailing edge/East Coast of the continental United States and biogenic reef/tropical islands.

The first demonstration, a trailing edge coast, was conducted at the U.S. Army Corps of Engineers (USACE) Engineering, Research & Development Center, Field Research Facility (FRF) in Duck, North Carolina. The second demonstration, a biogenic reef site, was conducted off the coast of the Pacific Missile Range Facility (PMRF) on the southwestern coast of Kauai, Hawaii.  Both demonstrations were successful in that all the required data were obtained and the behavior of the surrogates matched the predictions from the MM closely enough to allow calibration and validation of the MM for those coastal environments.

The UXO MM predicts which areas can safely be considered to contain immobile (or fully entombed) UXO and which UXO are at risk of moving into areas where they may come into contact with the public. The MM also aids planning for remediation purposes by indicating how long after a survey UXO will remain where they are found and what areas will stay free of UXO after remediation efforts are complete.